RESUMO
Researchers from diverse disciplines, including organismal and cellular physiology, sports science, human nutrition, evolution and ecology, have sought to understand the causes and consequences of the surprising variation in metabolic rate found among and within individual animals of the same species. Research in this area has been hampered by differences in approach, terminology and methodology, and the context in which measurements are made. Recent advances provide important opportunities to identify and address the key questions in the field. By bringing together researchers from different areas of biology and biomedicine, we describe and evaluate these developments and the insights they could yield, highlighting the need for more standardisation across disciplines. We conclude with a list of important questions that can now be addressed by developing a common conceptual and methodological toolkit for studies on metabolic variation in animals.
Assuntos
Metabolismo Basal , Animais , Humanos , FenótipoRESUMO
BACKGROUND: Circadian rhythm is altered in individuals with obesity and insulin resistance, showing a smaller amplitude, less stability, and increased intradaily variation. OBJECTIVE: We compared reproducibility of circadian-rhythm parameters over time and under free-living vs. controlled conditions in participants with obesity and pre-diabetes after 2- and 3-year weight-loss maintenance during the 3-year PREVIEW (PREVention of diabetes through lifestyle intervention and population studies In Europe and around the World) study. Associations of obesity and insulin resistance with circadian-rhythm parameters were assessed. SUBJECTS AND METHODS: Circadian-rhythm parameters were determined using continuous wrist-temperature measurements in free-living environments at year 2 (n = 24; age 56.8 ± 10.3 y; body mass index (BMI) = 30 ± 3.9 kg/m2; homeostatic model assessment of insulin resistance (HOMA-IR) 2.4 ± 1.1), at year 3 (n = 97; age 61.7 ± 7.8; BMI = 29.7 ± 3.9; HOMA-IR 2.9 ± 2.1), and at year 3 in a controlled condition (n = 38; age 63.4 ± 6.7; BMI = 28.7 ± 3.9; HOMA-IR 3.8 ± 1.4). Reproducibility was assessed by analyzing repeatability coefficients (CR), differences, and associations, over time as well as between conditions. Associations of BMI and HOMA-IR with circadian-rhythm parameters were assessed at y-3 in both conditions using factor analysis, followed by Pearson's correlations. RESULTS: Reproducibility of circadian-rhythm parameters over time in the free-living environments was high (CR 0.002-5.26; no significant differences; associated amplitudes r = 0.57; p < 0.01). In contrast, reproducibility between different conditions was low (CR 0.02-11.36; significant differences between most parameters (p < 0.05); yet associated amplitudes r = 0.59; p < 0.01). In the controlled vs. free-living condition circadian-rhythm was more stable; BMI and HOMA-IR were associated with the physiological amplitude-related parameters (r = -0.45; p < 0.01; r = -0.33; p < 0.05). In the free-living environment, BMI and behavioral circadian-rhythm parameters indicating circadian alignment, contributed most to the explained variation (47.1%), and were inversely associated (r = -0.22; p < 0.05), while HOMA-IR was inversely associated with stability-related circadian-rhythm parameters (r = -0.21; p < 0.05). CONCLUSIONS: Circadian rhythm was highly reproducible over time in the free-living environments, yet different under different conditions, being more stable in the controlled condition. BMI may play a significant role in circadian alignment and vice versa in the free-living environment.
Assuntos
Ritmo Circadiano/fisiologia , Resistência à Insulina/fisiologia , Obesidade/complicações , Idoso , Índice de Massa Corporal , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Weight loss has been associated with adaptations in energy expenditure. Identifying factors that counteract these adaptations are important for long-term weight loss and weight maintenance. OBJECTIVE: The aim of this study was to investigate whether increased protein/carbohydrate ratio would reduce adaptive thermogenesis (AT) and the expected positive energy balance (EB) during weight maintenance after weight loss in participants with prediabetes in the postobese state. METHODS: In 38 participants, the effects of 2 diets differing in protein/carbohydrate ratio on energy expenditure and respiratory quotient (RQ) were assessed during 48-h respiration chamber measurements â¼34 mo after weight loss. Participants consumed a high-protein (HP) diet (n = 20; 13 women/7 men; age: 64.0 ± 6.2 y; BMI: 28.9 ± 4.0 kg/m 2) with 25:45:30% or a moderate-protein (MP) diet (n = 18; 9 women/9 men; age: 65.1 ± 5.8 y; BMI: 29.0 ± 3.8 kg/m 2) with 15:55:30% of energy from protein:carbohydrate:fat. Predicted resting energy expenditure (REEp) was calculated based on fat-free mass and fat mass. AT was assessed by subtracting measured resting energy expenditure (REE) from REEp. The main outcomes included differences in components of energy expenditure, substrate oxidation, and AT between groups. RESULTS: EB (MP = 0.2 ± 0.9 MJ/d; HP = -0.5 ± 0.9 MJ/d) and RQ (MP = 0.84 ± 0.02; HP = 0.82 ± 0.02) were reduced and REE (MP: 7.3 ± 0.2 MJ/d compared with HP: 7.8 ± 0.2 MJ/d) was increased in the HP group compared with the MP group (P < 0.05). REE was not different from REEp in the HP group, whereas REE was lower than REEp in the MP group (P < 0.05). Furthermore, EB was positively related to AT (rs = 0.74; P < 0.001) and RQ (rs = 0.47; P < 0.01) in the whole group of participants. CONCLUSIONS: In conclusion, an HP diet compared with an MP diet led to a negative EB and counteracted AT â¼34 mo after weight loss, in participants with prediabetes in the postobese state. These results indicate the relevance of compliance to an increased protein/carbohydrate ratio for long-term weight maintenance after weight loss. The trial was registered at clinicaltrials.gov as NCT01777893.
Assuntos
Proteínas Alimentares/administração & dosagem , Metabolismo Energético , Estado Pré-Diabético/metabolismo , Termogênese , Redução de Peso , Idoso , Biomarcadores/urina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fenômenos Fisiológicos da Nutrição , Obesidade/metabolismo , Obesidade/fisiopatologia , Obesidade/terapia , Estado Pré-Diabético/fisiopatologiaRESUMO
Morbidly obese patients are most successfully treated with bariatric surgery. Although restrictive gastric surgery physically limits food intake, it is also suggested that eating behavior and food-reward mechanisms are affected. Therefore, eating behavior and food-reward were assessed in ten patients that underwent gastric volume reduction by endoscopic gastroplication. Patients participated in test days before and one, three and twelve months after the procedure. Weight loss, food intake, appetite, gastric emptying rate, food-reward (i.e. liking and wanting) and eating behavior were assessed. Body mass index decreased from 38.3 (37.6-42.6) to 33.9 (31.0-35.9) kg/m2 after one year. Ad libitum food intake decreased significantly after one month, but not after one year. Gastric emptying rate did not change. AUC of VAS scores for desire to eat, quantity, fullness, hunger, snacking and satiety changed after one month, but not all remained significantly changed after one year. Thirst did not change. Liking scores of food items decreased significantly in the fasted as well as the satiated state after the procedure. Wanting scores did not change. Uncontrolled eating decreased significantly after three and twelve months; emotional eating was only significantly decreased after three months. The results show that food intake decreases, while VAS scores for appetite and eating behavior change accordingly. Liking, but not wanting of food items changed to benefit the weight losing patient. The effects were stronger at one-month follow-up than at 12 months, which may be a risk of relapse after initial successful weight loss. The effects of new bariatric procedures on food-reward should be studied in future randomized trials to further elucidate their impact. REGISTERED AT CLINICALTRIALS. GOV: NCT02381340.
Assuntos
Ingestão de Alimentos/psicologia , Comportamento Alimentar/psicologia , Gastroplastia/psicologia , Obesidade Mórbida/psicologia , Recompensa , Adulto , Apetite , Índice de Massa Corporal , Estudos de Viabilidade , Feminino , Esvaziamento Gástrico/fisiologia , Gastroplastia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/fisiopatologia , Obesidade Mórbida/cirurgia , Projetos Piloto , Período Pós-Operatório , Resultado do TratamentoRESUMO
BACKGROUND: Green tea (GT) extract may play a role in body weight regulation. Suggested mechanisms are decreased fat absorption and increased energy expenditure. OBJECTIVE: We examined whether GT supplementation for 12 wk has beneficial effects on weight control via a reduction in dietary lipid absorption as well as an increase in resting energy expenditure (REE). METHODS: Sixty Caucasian men and women [BMI (in kg/m²): 18-25 or >25; age: 18-50 y] were included in a randomized placebo-controlled study in which fecal energy content (FEC), fecal fat content (FFC), resting energy expenditure, respiratory quotient (RQ), body composition, and physical activity were measured twice (baseline vs. week 12). For 12 wk, subjects consumed either GT (>0.56 g/d epigallocatechin gallate + 0.28-0.45 g/d caffeine) or placebo capsules. Before the measurements, subjects recorded energy intake for 4 consecutive days and collected feces for 3 consecutive days. RESULTS: No significant differences between groups and no significant changes over time were observed for the measured variables. Overall means ± SDs were 7.2 ± 3.8 g/d, 6.1 ± 1.2 MJ/d, 67.3 ± 14.3 kg, and 29.8 ± 8.6% for FFC, REE, body weight, and body fat percentage, respectively. CONCLUSION: GT supplementation for 12 wk in 60 men and women did not have a significant effect on FEC, FFC, REE, RQ, and body composition.
Assuntos
Fármacos Antiobesidade/uso terapêutico , Camellia sinensis/química , Gorduras na Dieta/metabolismo , Suplementos Nutricionais , Absorção Intestinal , Sobrepeso/prevenção & controle , Extratos Vegetais/uso terapêutico , Adiposidade , Adolescente , Adulto , Metabolismo Basal , Índice de Massa Corporal , Gorduras na Dieta/antagonistas & inibidores , Fezes/química , Feminino , Manipulação de Alimentos , Fármacos Gastrointestinais/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Sobrepeso/metabolismo , Folhas de Planta/química , Método Simples-Cego , Adulto JovemRESUMO
A low fat oxidative capacity has been linked to muscle diacylglycerol (DAG) accumulation and insulin resistance. Alternatively, a low fat oxidation rate may stimulate glucose oxidation, thereby enhancing glucose disposal. Here, we investigated whether an ethyl-2-[6-(4-chlorophenoxy)hexyl]-oxirane-2-carboxylate (etomoxir)-induced inhibition of fat oxidation leads to muscle fat storage and insulin resistance. An intervention in healthy male subjects was combined with studies in human primary myotubes. Furthermore, muscle DAG and triacylglycerol (TAG), mitochondrial function, and insulin signaling were examined in etomoxir-treated C57bl6 mice. In humans, etomoxir administration increased glucose oxidation at the expense of fat oxidation. This effect was accompanied by an increased abundance of GLUT4 at the sarcolemma and a lowering of plasma glucose levels, indicative of improved glucose homeostasis. In mice, etomoxir injections resulted in accumulation of muscle TAG and DAG, yet improved insulin-stimulated GLUT4 translocation. Also in human myotubes, insulin signaling was improved by etomoxir, in the presence of increased intramyocellular lipid accumulation. These insulin-sensitizing effects in mice and human myotubes were accompanied by increased phosphorylation of AMP-activated protein kinase (AMPK). Our results show that a reduction in fat oxidation leading to accumulation of muscle DAG does not necessarily lead to insulin resistance, as the reduction in fat oxidation may activate AMPK.
Assuntos
Diglicerídeos/metabolismo , Compostos de Epóxi/farmacologia , Ácidos Graxos/metabolismo , Resistência à Insulina/fisiologia , Mitocôndrias/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Triglicerídeos/metabolismo , Análise de Variância , Animais , Western Blotting , Imunofluorescência , Transportador de Glucose Tipo 4/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Fibras Musculares Esqueléticas/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Sarcolema/metabolismoRESUMO
PURPOSE OF REVIEW: The review addresses briefly the relevance of protein diets for body weight loss and weight maintenance. The addition of recent findings on age-dependent protein requirements, specific effects of protein intake and protein source, the relevance of the other dietary macronutrients, especially of 'low-carb', 'protein leverage', the mechanisms of protein-induced satiety, and food-reward makes the review up-to-date. RECENT FINDINGS: Different effects of protein diets in different age groups result from age-dependent protein requirements that are primarily related to effects on body composition. A protein intake of 0.8âg/kg/day is sufficient to sustain a negative energy balance in adults, irrespective of the protein source. 'Low-carb' diets trace back to the protein-induced effects. Evidence that protein intake drives energy intake as suggested by the 'Protein leverage hypothesis' is scarce and equivocal. Finally, limited protein-induced food reward may affect compliance to a protein diet. SUMMARY: An implication of the findings for clinical practice is that a protein intake of 0.8-1.2âg/kg/day is sufficient to sustain satiety, energy expenditure, and fat-free mass, independent of a dietary 'low-carb' content. Limited protein-induced food reward may affect compliance to a protein diet.
Assuntos
Peso Corporal , Proteínas Alimentares/administração & dosagem , Homeostase , Redução de Peso , Apetite/fisiologia , Composição Corporal , Dieta , Dieta com Restrição de Proteínas/efeitos adversos , Ingestão de Energia , Metabolismo Energético , Humanos , Leucina/administração & dosagem , Ensaios Clínicos Controlados Aleatórios como Assunto , SaciaçãoRESUMO
Addition of capsaicin (CAPS) to the diet has been shown to increase satiety; therefore, CAPS is of interest for anti-obesity therapy. We investigated the effects of CAPS on appetite profile and ad libitum energy intake in relation to energy balance. Fifteen subjects (seven women and eight men, age: 29.7 ± 10.8yrs, BMI: 23.3 ± 2.9 kg/m(2)) underwent four conditions in a randomized crossover design in 36 hour sessions in a respiration chamber; they received 100% of their daily energy requirements in the conditions "100%Control" and "100%CAPS", and 75% of their daily energy requirements in the conditions "75%Control" and "75%CAPS", followed by an ad libitum dinner. In the 100%CAPS and 75%CAPS conditions, CAPS was given at a dose of 2.56 mg (1.03 g of red chili pepper, 39,050 Scoville heat units) with every meal. Satiety (P < 0.05) and fullness (P = 0.01) were measured every waking hour and before and after every meal using visual analogue scales, and were higher in the 100%CAPS versus 100%Control condition. After dinner desire to eat, satiety and fullness did not differ between 75%CAPS and 100%Control, while desire to eat was higher (P < 0.05) and satiety (P = 0.06) and fullness (P = 0.06) tended to be lower in the 75%Control versus 100%Control condition. Furthermore, ad libitum intake (P = 0.07) and overconsumption (P = 0.06) tended to decrease in 100%CAPS versus 100%Control. In energy balance, addition of capsaicin to the diet increases satiety and fullness, and tends to prevent overeating when food intake is ad libitum. After dinner, capsaicin prevents the effects of the negative energy balance on desire to eat.
Assuntos
Apetite/efeitos dos fármacos , Capsaicina/farmacologia , Capsicum/química , Ingestão de Energia/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Hiperfagia/prevenção & controle , Saciação/efeitos dos fármacos , Adolescente , Adulto , Dieta , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético , Feminino , Humanos , Fome , Masculino , Refeições , Pessoa de Meia-Idade , Obesidade/prevenção & controle , Resposta de Saciedade/efeitos dos fármacos , Sensação , Método Simples-Cego , Adulto JovemRESUMO
Energy intake restriction causes a yo-yo effect by decreasing energy expenditure (EE) and decreasing fullness. We investigated the 24-h effect of protein and capsaicin, singly or combined, on fullness and EE during 20% energy intake restriction. The 24 participants (12 male, 12 female; BMI, 25.2 ± 0.4 kg/m(2); age, 27 ± 4 y; body fat, 25.6 ± 5.7%; 3-factor eating questionnaire, F1: 6 ± 2, F2: 4 ± 2, F3: 3 ± 2) underwent eight 36-h sessions in a respiration chamber. The study had a randomized crossover design with 8 randomly sequenced conditions. The participants were fed 100 or 80% of their daily energy requirements. There were 2 control (C) conditions: 100%C and 80%C; 2 conditions with capsaicin (Caps): 100%Caps and 80%Caps; 2 conditions with elevated protein (P): 100%P and 80%P; and 2 conditions with a mixture of protein and capsaicin (PCaps): 100%PCaps and 80%PCaps. Appetite profile, EE, and substrate oxidation were monitored. Compared with 100%C, the 80%C group had expected negative energy-balance effects with respect to total EE, diet-induced thermogenesis, and fullness, whereas the 80%Caps diet counteracted these effects, and the 80%P and 80%PCaps diets exceeded these effects (P < 0.01). In energy balance and negative energy balance, fat balance was more negative in the 80%Caps, P, and PCaps groups than in the 80%C group (P < 0.05) and respiratory quotient values were lower. A negative protein balance was prevented with the 80%P and 80%PCaps diets compared with the 80%C diet. Our results suggest that protein and capsaicin, consumed singly or mixed, counteracted the energy intake restriction effects on fullness and EE. During energy restriction, protein and capsaicin promoted a negative fat balance and protein treatments also prevented a negative protein balance.
Assuntos
Restrição Calórica , Capsaicina/administração & dosagem , Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Metabolismo Energético/fisiologia , Saciação/fisiologia , Adulto , Composição Corporal , Estudos Cross-Over , Gorduras na Dieta/metabolismo , Metabolismo Energético/efeitos dos fármacos , Feminino , Humanos , Masculino , Consumo de Oxigênio , Saciação/efeitos dos fármacos , TermogêneseRESUMO
Energy-restricted high-protein diets (HPDs) have shown favorable results for body weight (BW) management, yet studies differ in their outcomes depending on the dietary protein content. Our objective was to determine the effects of dietary protein content on BW loss-related variables during a 6-mo energy restriction with the use of diets containing protein at the level of requirement [normal-protein diet (NPD), 0.8 g · kg BW(-1) (.) d(-1)] and above (HPD, 1.2 g · kg BW(-1) (.) d(-1)). In overweight and obese participants (24 men and 48 women), BW, body composition, and metabolic responses were assessed before and after subsequent energy intakes of 100, 33, and 67% of the original individual daily energy requirements. Protein intake was consistent in the NPD (0.8 ± 0.3 g · kg BW(-1) (.) d(-1)) and HPD (1.2 ± 0.3 g · kg BW(-1) (.) d(-1)) groups throughout the study (P < 0.001). BMI and body fat mass similarly decreased in the NPD and HPD groups (P < 0.01). Fat free mass (FFM), resting energy expenditure (REE) compared with predicted REE, and diastolic blood pressure (DBP) changed favorably with the HPD compared with the NPD group after BW loss (P < 0.05). A NPD of 0.8 g · kg BW(-1) (.) d(-1) is sufficient for BW management, whereas a HPD of 1.2 g · kg BW(-1) (.) d(-1) is necessary for preservation of REE and a stronger initial sparing effect of FFM and lowering of DBP.
Assuntos
Metabolismo Basal/efeitos dos fármacos , Compartimentos de Líquidos Corporais/efeitos dos fármacos , Dieta Redutora , Proteínas Alimentares/administração & dosagem , Ingestão de Energia , Obesidade/dietoterapia , Redução de Peso/efeitos dos fármacos , Tecido Adiposo , Adulto , Índice de Massa Corporal , Restrição Calórica , Proteínas Alimentares/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Necessidades NutricionaisRESUMO
In addition to short sleep duration, reduced sleep quality is also associated with appetite control. The present study examined the effect of sleep fragmentation, independent of sleep duration, on appetite profiles and 24 h profiles of hormones involved in energy balance regulation. A total of twelve healthy male subjects (age 23 (sd 4) years, BMI 24·4 (sd 1·9) kg/m²) completed a 24 h randomised crossover study in which sleep (23.30-07.30 hours) was either fragmented or non-fragmented. Polysomnography was used to determine rapid-eye movement (REM) sleep, slow-wave sleep (SWS) and total sleep time (TST). Blood samples were taken at baseline and continued hourly for the 24 h period to measure glucose, insulin, ghrelin, leptin, glucagon-like peptide 1 (GLP-1) and melatonin concentrations. In addition, salivary cortisol levels were measured. Visual analogue scales were used to score appetite-related feelings. Sleep fragmentation resulted in reduced REM sleep (69·4 min compared with 83·5 min; P< 0·05) and preservation of SWS without changes in TST. In fragmented v. non-fragmented sleep, glucose concentrations did not change, while insulin secretion was decreased in the morning, and increased in the afternoon (P< 0·05), and GLP-1 concentrations and fullness scores were lower (P< 0·05). After dinner, desire-to-eat ratings were higher after fragmented sleep (P< 0·05). A single night of fragmented sleep, resulting in reduced REM sleep, induced a shift in insulin concentrations, from being lower in the morning and higher in the afternoon, while GLP-1 concentrations and fullness scores were decreased. These results may lead to increased food intake and snacking, thus contributing to a positive energy balance.
Assuntos
Apetite/fisiologia , Privação do Sono/sangue , Sono/fisiologia , Adulto , Regulação do Apetite , Glicemia/análise , Ingestão de Alimentos , Metabolismo Energético , Grelina/sangue , Peptídeo 1 Semelhante ao Glucagon/sangue , Voluntários Saudáveis , Hormônios/sangue , Humanos , Hidrocortisona/sangue , Insulina/sangue , Insulina/metabolismo , Secreção de Insulina , Leptina/sangue , Masculino , Melatonina/sangue , Polissonografia , Sono REM/fisiologia , Inquéritos e Questionários , Fatores de Tempo , Adulto JovemRESUMO
Extreme macronutrient intakes possibly lead to different brain signalling. The aim of the present study was to determine the effects of ingesting high-protein v. high-carbohydrate food on liking and wanting task-related brain signalling (TRS) and subsequent macronutrient intake. A total of thirty female subjects (21.6 (SD 2.2) years, BMI 25.0 (SD 3.7) kg/m²) completed four functional MRI scans: two fasted and two satiated on two different days. During the scans, subjects rated all food items for liking and wanting, thereby choosing the subsequent meal. The results show that high-protein (PROT) v. high-carbohydrate (CARB) conditions were generated using protein or carbohydrate drinks at the first meal. Energy intake and hunger were recorded. PROT (protein: 53.7 (SD 2.1) percentage of energy (En%); carbohydrate: 6.4 (SD 1.3) En%) and CARB conditions (protein: 11.8 (SD 0.6) En%; carbohydrate: 70.0 (SD 2.4) En%) were achieved during the first meal, while the second meals were not different between the conditions. Hunger, energy intake, and behavioural liking and wanting ratings were decreased after the first meal (P< 0.001). Comparing the first with the second meal, the macronutrient content changed: carbohydrate -26.9 En% in the CARB condition, protein -37.8 En% in the PROT condition. After the first meal in the CARB condition, wanting TRS was increased in the hypothalamus. After the first meal in the PROT condition, liking TRS was decreased in the putamen (P< 0.05). The change in energy intake from the first to the second meal was inversely related to the change in liking TRS in the striatum and hypothalamus in the CARB condition and positively related in the PROT condition (P< 0.05). In conclusion, wanting and liking TRS were affected differentially with a change in carbohydrate or protein intake, underscoring subsequent energy intake and shift in macronutrient composition.
Assuntos
Encéfalo/metabolismo , Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Preferências Alimentares , Neurônios/metabolismo , Transmissão Sináptica , Adulto , Índice de Massa Corporal , Corpo Estriado/metabolismo , Ingestão de Energia , Feminino , Humanos , Fome , Hipotálamo/metabolismo , Imageamento por Ressonância Magnética , Refeições , Países Baixos , Putamen/metabolismo , Recompensa , Adulto JovemRESUMO
OBJECTIVE: The aim of this study was an assessment of post hoc associations among circadian rhythm parameters, physical activity (PA), and cardiometabolic risk factors in adults with obesity and prediabetes after 3 years of weight loss maintenance. METHODS: Circadian rhythm parameters (continuous wrist-temperature measurements), PA, systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), plasma high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, remnant cholesterol, triacylglycerol, and C-reactive protein (CRP) concentrations were determined in 91 free-living participants (mean [SD], age = 56.6 [10] years; BMI = 28.2 [4.0]; homeostatic model assessment of insulin resistance [HOMA-IR] = 3.2 [3.1]) and in 38 participants in sedentary respiration chamber conditions (age = 56.6 [10] years; BMI = 28.5 [4.0]; HOMA-IR = 3.3 [1.4]). Associations of circadian rhythm parameters and PA with cardiometabolic risk factors were determined using factor analyses followed by Pearson correlations. RESULTS: Values of cardiometabolic risk factors were similar, whereas circadian rhythm parameters and PA differed significantly (p < 0.05) between conditions. In both conditions, parameters indicating a robust circadian rhythm associated inversely with CRP and positively with plasma HDL-C concentrations. In free-living conditions, PA associated inversely with SBP and HR and positively with HDL-C and robust circadian rhythm parameters. In sedentary conditions, PA associated positively with HR and inversely with robust circadian rhythm parameters. PA mediated the inverse association of parameters indicating a robust circadian rhythm with SBP in free-living conditions. CONCLUSIONS: In adults with obesity and prediabetes, parameters indicating a robust circadian rhythm were, independently of PA, associated with lower cardiometabolic risk and CRP. Only in free-living conditions, PA mediated the association of higher circadian stability with lower SBP.
Assuntos
Doenças Cardiovasculares , Estado Pré-Diabético , Adulto , Humanos , Pessoa de Meia-Idade , Fatores de Risco Cardiometabólico , Obesidade , Exercício Físico , Colesterol , Pressão Sanguínea , Estilo de Vida , Fatores de Risco , Índice de Massa CorporalRESUMO
Obesity is a serious health problem because of its co-morbidities. The solution, implying weight loss and long-term weight maintenance, is conditional on: (i) sustained satiety despite negative energy balance, (ii) sustained basal energy expenditure despite BW loss due to (iii) a sparing of fat-free mass (FFM), being the main determinant of basal energy expenditure. Dietary protein has been shown to assist with meeting these conditions, since amino acids act on the relevant metabolic targets. This review deals with the effects of different protein diets during BW loss and BW maintenance thereafter. Potential risks of a high protein diet are dealt with. The required daily intake is 0·8-1·2 g/kg BW, implying sustaining the original absolute protein intake and carbohydrate and fat restriction during an energy-restricted diet. The intake of 1·2 g/kg BW is beneficial to body composition and improves blood pressure. A too low absolute protein content of the diet contributes to the risk of BW regain. The success of the so-called 'low carb' diet that is usually high in protein can be attributed to the relatively high-protein content per se and not to the relatively lower carbohydrate content. Metabolic syndrome parameters restore, mainly due to BW loss. With the indicated dosage, no kidney problems have been shown in healthy individuals. In conclusion, dietary protein contributes to the treatment of obesity and the metabolic syndrome, by acting on the relevant metabolic targets of satiety and energy expenditure in negative energy balance, thereby preventing a weight cycling effect.
Assuntos
Dieta Redutora , Proteínas Alimentares/uso terapêutico , Ingestão de Energia , Metabolismo Energético/efeitos dos fármacos , Obesidade/dietoterapia , Saciação/efeitos dos fármacos , Redução de Peso/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Composição Corporal/efeitos dos fármacos , Dieta com Restrição de Carboidratos , Saúde , Humanos , Síndrome Metabólica/dietoterapia , Necessidades NutricionaisRESUMO
Increased gluconeogenesis (GNG) has been suggested to contribute to protein-induced satiety via modulation of glucose homoeostasis. The objective was to determine GNG and appetite in healthy human subjects after a high-protein v. a normal-protein diet and to assess whether GNG contributes to protein-induced satiety. A total of twenty-two healthy subjects (ten men and twelve women: age 23 (sem 1) years, BMI 22·1 (sem 0·5) kg/m²) received an isoenergetic high-protein (30/0/70 % of energy from protein/carbohydrate/fat) or normal-protein diet (12/55/33 % of energy from protein/carbohydrate/fat) for 1·5 d in a randomised cross-over design. Appetite ratings were measured using visual analogue scales (VAS); endogenous glucose production and GNG were measured via infusion of [6,6-²H2]glucose and ingestion of ²H2O. Moreover, fasting glucose and ß-hydroxybutyrate concentrations were measured. Glycogen stores were lowered at the start with a glycogen-lowering exercise test. During the high-protein compared with the normal-protein diet, GNG was increased and appetite was suppressed (GNG: 148 (sem 7) v. 133 (sem 6) g/24 h, P < 0·05; and 24 h area under the curve for hunger: 694 (sem 46) v. 1055 (sem 52) mm VAS × 24 h, P < 0·001; fullness: 806 (sem 59) v. 668 (sem 64) mm VAS × 24 h, P < 0·05; desire to eat: 762 (sem 48) v. 1004 (sem 66) mm VAS × 24 h, P < 0·001). There was no correlation between appetite ratings and GNG. Glucose concentration was lower (4·09 (sem 0·10) v. 4·89 (sem 0·06) mmol/l, P < 0·001) and ß-hydroxybutyrate concentration was higher (1349 (sem 139) v. 234 (sem 25) µmol/l, P < 0·001) after the high-protein compared with the normal-protein diet. In conclusion, after a high-protein diet, GNG was increased and appetite was lower compared with a normal-protein diet; however, these were unrelated to each other. An increased concentration of ß-hydroxybutyrate may have contributed to appetite suppression on the high-protein diet.
Assuntos
Depressores do Apetite/administração & dosagem , Proteínas Alimentares/administração & dosagem , Gluconeogênese , Resposta de Saciedade , Ácido 3-Hidroxibutírico/sangue , Adulto , Regulação do Apetite , Glicemia/análise , Índice de Massa Corporal , Estudos Cross-Over , Metabolismo Energético , Feminino , Glicogênio/metabolismo , Homeostase , Humanos , Masculino , Método Simples-Cego , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND & AIMS: The association of quantity and quality of carbohydrate sources with appetite during long-term weight-loss maintenance (WLM) after intentional weight loss (WL) is unclear. We aimed to investigate longitudinal associations of quantity and quality of carbohydrate sources with changes in subjective appetite sensations during WLM. METHODS: This secondary analysis evaluated longitudinal data from the 3-year WLM phase of the PREVIEW study, a 2 × 2 factorial (diet-physical activity arms), multi-center, randomized trial. 1279 individuals with overweight or obesity and prediabetes (25-70 years; BMI≥25 kg m-2) were included. Individuals were merged into 1 group to assess longitudinal associations of yearly changes in appetite sensations. Quantity and quality of carbohydrate sources including total carbohydrate, glycemic index (GI), glycemic load (GL), and total dietary fiber were assessed via 4-day food diaries at 4 timepoints (26, 52, 104, and 156 weeks) during WLM. Visual analog scales were used to assess appetite sensations in the previous week. RESULTS: During WLM, participants consumed on average 160.6 (25th, 75th percentiles 131.1, 195.8) g·day-1 of total carbohydrate, with GI 53.8 (48.7, 58.8) and GL 85.3 (67.2, 108.9) g day-1, and 22.3 (17.6, 27.3) g·day-1 of dietary fiber. In the available-case analysis, multivariable-adjusted linear mixed models with repeated measures showed that each 30-g increment in total carbohydrate was associated with increases in hunger (1.36 mm year-1, 95% CI 0.77, 1.95, P < 0.001), desire to eat (1.10 mm year-1, 0.59, 1.60, P < 0.001), desire to eat something sweet (0.99 mm year-1, 0.30, 1.68, P = 0.005), and weight regain (0.20%·year-1, 0.03, 0.36, P = 0.022). Increasing GI was associated with weight regain, but not associated with increases in appetite sensations. Each 20-unit increment in GL was associated with increases in hunger (0.92 mm year-1, 0.33, 1.51, P = 0.002), desire to eat (1.12 mm year-1, 0.62, 1.62, P < 0.001), desire to eat something sweet (1.13 mm year-1, 0.44, 1.81, P < 0.001), and weight regain (0.35%·year-1, 0.18, 0.52, P < 0.001). Surprisingly, dietary fiber was also associated with increases in desire to eat, after adjustment for carbohydrate or GL. CONCLUSIONS: In participants with moderate carbohydrate and dietary fiber intake, and low to moderate GI, we found that higher total carbohydrate, GL, and total fiber, but not GI, were associated with increases in subjective desire to eat or hunger over 3 years. This study was registered as ClinicalTrials.gov, NCT01777893.
Assuntos
Apetite/fisiologia , Manutenção do Peso Corporal/fisiologia , Carboidratos da Dieta/administração & dosagem , Fibras na Dieta/administração & dosagem , Sobrepeso/fisiopatologia , Redução de Peso/fisiologia , Adulto , Idoso , Índice de Massa Corporal , Feminino , Índice Glicêmico , Carga Glicêmica , Humanos , Fome/fisiologia , Masculino , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Obesidade/terapia , Sobrepeso/terapia , Estado Pré-Diabético/fisiopatologia , Estado Pré-Diabético/terapiaRESUMO
OBJECTIVE: To examine whether the effect of a 3-year lifestyle intervention on body weight and cardiometabolic risk factors differs by prediabetes metabolic phenotype. RESEARCH DESIGN AND METHODS: This post hoc analysis of the multicenter, randomized trial, PREVention of diabetes through lifestyle interventions and population studies In Europe and around the World (PREVIEW), included 1,510 participants with prediabetes (BMI ≥25 kg â m-2; defined using oral glucose tolerance tests). Of these, 58% had isolated impaired fasting glucose (iIFG), 6% had isolated impaired glucose tolerance (iIGT), and 36% had IFG+IGT; 73% had normal hemoglobin A1c (HbA1c; <39 mmol â mol-1) and 25% had intermediate HbA1c (39-47 mmol â mol-1). Participants underwent an 8-week diet-induced rapid weight loss, followed by a 148-week lifestyle-based weight maintenance intervention. Linear mixed models adjusted for intervention arm and other confounders were used. RESULTS: In the available-case and complete-case analyses, participants with IFG+IGT had greater sustained weight loss after lifestyle intervention (adjusted mean at 156 weeks -3.5% [95% CI, -4.7%, -2.3%]) than those with iIFG (mean -2.5% [-3.6%, -1.3%]) relative to baseline (P = 0.011). Participants with IFG+IGT and iIFG had similar cardiometabolic benefits from the lifestyle intervention. The differences in cardiometabolic benefits between those with iIGT and IFG+IGT were minor or inconsistent in different analyses. Participants with normal versus intermediate HbA1c had similar weight loss over 3 years and minor differences in cardiometabolic benefits during weight loss, whereas those with normal HbA1c had greater improvements in fasting glucose, 2-h glucose (adjusted between-group difference at 156 weeks -0.54 mmol â L-1 [95% CI -0.70, -0.39], P < 0.001), and triglycerides (difference -0.07 mmol â L-1 [-0.11, -0.03], P < 0.001) during the lifestyle intervention. CONCLUSIONS: Individuals with iIFG and IFG+IGT had similar improvements in cardiometabolic health from a lifestyle intervention. Those with normal HbA1c had greater improvements than those with intermediate HbA1c.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Intolerância à Glucose , Estado Pré-Diabético , Humanos , Estado Pré-Diabético/epidemiologia , Hemoglobinas Glicadas/metabolismo , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/epidemiologia , Estilo de Vida , Jejum , Glucose , Fenótipo , Redução de Peso , Peso CorporalRESUMO
BACKGROUND: The relationship between hypothalamus/pituitary/adrenal (HPA) axis functioning and (visceral) obesity may be explained by single-nucleotide polymorphisms (SNPs) of the HPA axis. Objective To investigate the relationship between the HPA axis SNP's 'BclI' in the glucocorticoid receptor gene and C8246T in the POMC gene and anthropometric measurements, body composition, 5-h cortisol concentrations, HPA axis feedback sensitivity, as well as HPA axis feedback sensitivity under stress in men and women. DESIGN/SUBJECTS/MEASUREMENTS: We assessed in 92 men and 102 women (18-55 years, BMI 19-41 kg/m(2) ) anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5-h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test and HPA axis functioning under a challenged condition consisting of a standardized high intensity test with ingestion of 4 mg dexamethasone. RESULTS: In female participants, the 8246C allele carriers compared to the 8246T allele carries were associated with a higher 5-h cortisol exposure (1·52 × 10(5) ± 0·8 vs 1·18 × 10(5) ± 0·6 nm·min, P < 0·05) and higher baseline postdexamethasone cortisol concentrations (54·5 ± 35·6 vs 37·4 ± 18·5 nm, P < 0·05). In male participants regarding the C8246T allele carriers and in both male and female participants regarding the BclI genotypes, no significant differences in anthropometric measurements, body composition and HPA axis functioning were observed. Multiple regression analysis showed that only increased 5-h cortisol exposure significantly related to changes in anthropometric measurements and body composition; the BclI and C8246T genotypes were not associated. CONCLUSION: Our preliminary data show that in both men and women (18-55 years, BMI 19-41 kg/m(2) ), the SNP's BclI and C8246T of the HPA axis were primarily related to altered HPA axis functioning, rather than to altered anthropometric measurements and body composition.
Assuntos
Sistema Hipotálamo-Hipofisário/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Polimorfismo de Nucleotídeo Único , Pró-Opiomelanocortina/genética , Receptores de Glucocorticoides/genética , Adolescente , Adulto , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/farmacologia , Composição Corporal , Estatura , Índice de Massa Corporal , Peso Corporal , Dexametasona/administração & dosagem , Dexametasona/farmacologia , Teste de Esforço , Feminino , Frequência do Gene , Genótipo , Humanos , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Análise de Regressão , Relação Cintura-Quadril , Adulto JovemRESUMO
Meal pattern may influence hormone and appetite dynamics and food intake. The objective of the study was to determine the effects of staggered compared with nonstaggered meal consumption on hormone and appetite dynamics, food reward (i.e. "liking," "wanting"), and subsequent energy intake. The study was conducted in a randomized cross-over design. Participants (n = 38, age = 24 ± 6 y, BMI = 25.0 ± 3.1 kg/m(2)) came to the university twice for consumption of a 4-course lunch (40% of the daily energy requirements) in 0.5 h (nonstaggered) or in 2 h with 3 within-meal pauses (staggered) followed by ad libitum food intake. Throughout the test sessions, glucagon-like peptide (GLP)-1, peptide tyrosine-tyrosine (PYY(3-36)), ghrelin, appetite, and food reward were measured. In the staggered compared with nonstaggered meal condition, peak values of GLP-1, PYY(3-36), and satiety were lower and time to peak values were higher (P < 0.02); the nadir value of hunger was higher, and time to nadir values of ghrelin and hunger were higher (P < 0.0001). Prior to ad libitum food intake, GLP-1 concentrations and satiety ratings were greater, ghrelin concentrations and hunger ratings were smaller, and food "wanting" was less in the staggered compared with nonstaggered meal condition (P < 0.05). However, this did not affect ad libitum energy intake (1.7 ± 0.3 vs. 1.9 ± 0.2 MJ). In conclusion, staggered compared with nonstaggered meal consumption induces less pronounced hormone and appetite dynamics. Moreover, it results in higher final GLP-1 concentrations and satiety ratings, lower ghrelin concentrations and hunger ratings, and lower food "wanting" prior to ad libitum food intake. However, this was not translated into lower energy intake.
Assuntos
Regulação do Apetite , Ingestão de Energia , Comportamento Alimentar/psicologia , Período Pós-Prandial , Adulto , Estudos Cross-Over , Feminino , Grelina/sangue , Peptídeo 1 Semelhante ao Glucagon/sangue , Humanos , Fome , Masculino , Sobrepeso/prevenção & controle , Fragmentos de Peptídeos , Peptídeo YY/sangue , Recompensa , Saciação , Inquéritos e Questionários , Fatores de Tempo , Adulto JovemRESUMO
Diets higher in protein content result in increased satiety and energy expenditure. In the short term, gelatin showed stronger hunger suppression and less subsequent energy intake compared with other proteins. The present study investigated whether a supra-sustained gelatin-milk protein (GMP) diet promotes weight loss compared with a sustained milk protein (SMP) diet and a supra-sustained milk protein (SSMP) diet during an 8-week diet period. A total of seventy-two healthy subjects (31·2 (sd 4·8) kg/m2; 43 (sd 10) years) followed one of the three diets in a subject-specific amount: SMP, SSMP or GMP diet. During weeks 1-4, energy intake was 100 % of individual energy requirement: 10, 40 and 50 % of energy (En %) as protein, fat and carbohydrate, respectively (SMP diet), and 20, 30 and 50 En % as protein, fat and carbohydrate, respectively (SSMP diet or GMP diet). During weeks 5-8, energy intake was 33 % of individual energy requirement: 30, 35 and 35 En % as protein, fat and carbohydrate, respectively (SMP diet), and 60, 5 and 35 En % as protein, fat and carbohydrate, respectively (SSMP diet or GMP diet). Thus, absolute protein intake was kept constant throughout per subject. Significant decreases in BMI (P < 0·0001) were similar between the GMP ( - 1·7 (sd 0·5) kg/m2) and the SMP ( - 2·1 (sd 0·8) kg/m2) and SSMP ( - 1·6 (sd 0·5) kg/m2) diets. Decreases in fat-free mass (FFM), fat mass (FM) and FM %, and increases in FFM % were similar between the GMP and both control diets. Changes in RQ differed (P < 0·05) between the GMP ( - 0·01 (sd 0·06)) and SSMP ( - 0·04 (sd 0·04)) diets. Changes in HDL concentrations differed (P < 0·05) between the GMP ( - 0·21 (sd 0·18) mmol/l) and the SMP and SSMP diets ( - 0·08 (sd 0·18) mmol/l and - 0·09 (sd 0·26) mmol/l, respectively). In conclusion, a gelatin-milk protein diet does not induce more beneficial effects during an 8-week weight-loss period compared with a SMP or SSMP diet.