Environmental life cycle assessment of production of the high intensity sweetener steviol glycosides from Stevia rebaudiana leaf grown in Europe: The SWEET project.

Purpose: There is an increasing interest in the use of non-nutritive sweeteners to replace added sugar in food and beverage products for reasons of improving consumer health. Much work has been done to understand safety of sweeteners, but very little on sustainability. To address that gap, this study presents the results of a life cycle assessment (LCA) of production of rebaudioside A 60%, 95% pure (RA60) steviol glycoside mix from Stevia rebaudiana leaf grown in Europe. Methods: An attributional cradle-to-factory-gate life cycle assessment was conducted on growing of stevia leaves and extraction of steviol glycosides in Europe. Primary data were used from a case study supply chain. Results are reported in impact categories from the ReCiPe 2016 (H) method, with focus given to global warming potential, freshwater eutrophication, water consumption, and land use. Impacts are expressed both in terms of production mass and sweetness equivalence, a common metric for understanding high intensity sweetener potency. Sweetness equivalence of RA60 is typically 200 to 300 times that of sugar. Comparison of environmental impact is made to sugar (sucrose) produced from both cane and beets. The research is part of the EU project SWEET (sweeteners and sweetness enhancers: impact on health, obesity, safety, and sustainability). Results and discussion: Global warming potential for production of RA60 was found to be 20.25 kgCO2-eq/kgRA60 on a mass basis and 0.081 kgCO2-eq/kgSE on a sweetness equivalence basis. Field production of stevia leaves was found to be the main source of impact for most impact categories, and for all four focus categories. Extraction of the RA60 was the main source of impact for the others. Leaf processing and seedling propagation were minor contributors to life cycle impact. Removal of international transport from the supply chain reduced global warming potential by 18.8%. Compared with sugar on a sweetness equivalence basis, RA60 has approximately 5.7% to 10.2% the impact for global warming potential, 5.6% to 7.2% the impact for land use, and is lower across most other impact categories. Conclusion: This is the first LCA of steviol glycoside mix RA60 produced from leaf in Europe. The results indicate that RA60 can be used to reduce environmental impact of providing a sweet taste by replacing sugar across all impact categories. However, it is important to note that specific formulations in which RA60 is used will have a bearing on the final environmental impact of any food or beverage products. For solid foods, this requires further research. Supplementary Information: The online version contains supplementary material available at 10.1007/s11367-022-02127-9.

The association of dietary animal and plant protein with putative risk markers of colorectal cancer in overweight pre-diabetic individuals during a weight-reducing programme: a PREVIEW sub-study.

PURPOSE: Diets with increased protein content are popular strategies for body weight regulation, but the effect of such diets for the colonic luminal environment is unclear. We aimed to investigate the associations between putative colorectal cancer-related markers and total protein intake, plant and animal proteins, and protein from red and processed meat in pre-diabetic adults (> 25 years). METHODS: Analyses were based on clinical and dietary assessments at baseline and after 1 year of intervention. Protein intake was assessed from 4-day dietary records. Putative colorectal cancer-related markers identified from 24-h faecal samples collected over three consecutive days were: concentration of short-chain fatty acids, phenols, ammonia, and pH. RESULTS: In total, 79 participants were included in the analyses. We found a positive association between change in total protein intake (slope: 74.72 ± 28.84 µmol per g faeces/E%, p = 0.01), including animal protein intake (slope: 87.63 ± 32.04 µmol per g faeces/E%, p = 0.009), and change in faecal ammonia concentration. For change in ammonia, there was a dose-response trend from the most negative (lowest tertile) to the most positive (highest tertile) association (p = 0.01): in the high tertile, a change in intake of red meat was positively associated with an increase in ammonia excretion (slope: 2.0 ± 0.5 µmol per g faeces/g/day, p < 0.001), whereas no such association was found in the low and medium tertile groups. CONCLUSION: Increases in total and animal protein intakes were associated with higher excretion of ammonia in faeces after 1 year in overweight pre-diabetic adults undertaking a weight-loss intervention. An increase in total or relative protein intake, or in the ratio of animal to plant protein, was not associated with an increase in faeces of any of the other putative colorectal cancer risk markers. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01777893.

Long-term effects of increased protein intake after weight loss on intrahepatic lipid content and implications for insulin sensitivity: a PREVIEW study.

The aim of this study was to assess the effects of a weight maintenance period comprising two diets differing in protein intake, after weight loss, on intrahepatic lipid content and implications for insulin sensitivity. A total of 25 participants [body mass index (BMI): 31.1 (3.5 kg/m2; intrahepatic lipid (IHL): 8.7 (8.3%; fasting glucose: 6.4 (0.6 mmol/l; homeostatic model assessment for insulin resistance (HOMA-IR): 3.7 (1.6; Matsuda index: 3.4 (2.9] started an 8-wk low-energy diet followed by a 2-yr weight maintenance period with either high protein or medium protein dietary guidelines. At baseline, after 6 mo, and after 2 yr, IHL, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were determined by magnetic resonance spectroscopy/imaging. Glucose and insulin concentrations, determined during an oral glucose challenge, were used to assess the HOMA-IR and Matsuda insulin sensitivity index (ISI). Protein intake was measured with 24-h urinary nitrogen excretion. Protein intake, BMI, IHL, VAT, SAT, HOMA-IR, and ISI did not change differently between the groups during the intervention. In the whole group, BMI, IHL, VAT, SAT, HOMA-IR, and ISI were favorably changed at 6 mo and 2 yr compared with baseline ( P < 0.05). Mixed-model analysis showed that independent of BMI, protein intake (g/d) at 6 mo was inversely related to IHL (coefficient: -0.04; P < 0.05) and VAT (coefficient: -0.01; P < 0.05). Overall, IHL was positively related to HOMA-IR (coefficient: 0.10; P < 0.01) and inversely related to ISI (coefficient: -0.17; P < 0.01), independent of BMI. A 2-yr medium- to high-protein energy-restricted diet reduced IHL and VAT. Independently of changes in BMI, IHL was inversely related to insulin sensitivity.

The role of higher protein diets in weight control and obesity-related comorbidities.

The importance of the relative dietary content of protein, carbohydrate and the type of carbohydrate (that is, glycemic index (GI)) for weight control under ad libitum conditions has been controversial owing to the lack of large scale studies with high diet adherence. The Diet, Obesity and Genes (DioGenes) European multicentre trial examined the importance of a slight increase in dietary protein content, reduction in carbohydrate and the importance of choosing low (LGI) vs high GI (HGI) carbohydrates for weight control in 932 obese families. Only the adults underwent a diet of 800 kcal per day for 8 weeks, and after losing ~11kg they were randomized to one of five energy ad libitum diets for 6 months. The diets differed in protein content and GI. The high-protein (HP) diet groups consumed 5.4% points more energy from protein than the normal protein (NP) groups, and the LGI diet groups achieved 5.1% lower GI than the HGI groups. The effect of HP and LGI was additive on weight loss and maintenance, and the combination was successful in preventing weight regain and reducing drop-out rate among the adults after the 11kg weight loss. This diet also reduced body fatness and prevalence of overweight and obesity among their children and had consistent beneficial effects on blood pressure, blood lipids and inflammation in both parents and children. After 1 year, mainly the HP effects were maintained. Putative genes have been identified that suggest this diet to be particularly effective in 67% of the population. In conclusion, the DioGenes diet has shown to be effective for prevention of weight regain and for weight reduction in overweight children under ad libitum conditions. The less-restrictive dietary approach fits into a normal food culture, and has been translated into popular diet and cook books in several languages.

The effect of the triple monoamine reuptake inhibitor tesofensine on energy metabolism and appetite in overweight and moderately obese men.

BACKGROUND: Tesofensine (TE) is a new drug producing twice the weight loss in obese individuals as seen with currently marketed drugs. It inhibits the presynaptic reuptake of the neurotransmitters noradrenaline, dopamine and serotonin, and is thought to enhance the neurotransmission of all three monoamines. The mechanisms by which it produces weight loss in humans are unresolved. OBJECTIVE: The aim of this study is to investigate the mechanism(s) behind weight reduction by measuring energy expenditure and appetite sensations in overweight and obese individuals. DESIGN: Thirty-two healthy, overweight or moderately obese men were treated with 2.0 mg TE daily for 7 days followed by an additional 7 days with 1.0 mg TE daily or corresponding placebo (PL) in a randomized, controlled trial. They were instructed to maintain habitual food intake and physical activity throughout. Twenty-four-hour energy expenditure (24-h EE), fat oxidation and spontaneous physical activity were measured in a respiration chamber before and after treatment. Body composition was assessed by dual-energy X-ray absorption and appetite was evaluated by visual analogue scales in conjunction with a standardized dinner. RESULTS: Despite efforts to keep body weight and composition constant, TE induced a 1.8 kg weight loss above PL after 2 weeks' treatment (P<0.0001). TE also induced higher ratings of satiety and fullness and concomitantly lower prospective food intake than placebo. No significant effect of TE on total 24-h EE could be demonstrated compared with PL, but higher energy expenditure was observed during the night period (4.6%; P<0.05) when adjusted for changes in body composition. Furthermore, TE increased 24-h fat oxidation as compared with PL (18 g; P<0.001). CONCLUSION: TE has a pronounced effect on appetite sensations and a slight effect on energy expenditure at night-both effects can contribute to the strong weight-reducing effect of TE.

Influence of type of dairy matrix micro- and macrostructure on in vitro lipid digestion.

Recent research indicates that the food matrix can influence digestion kinetics and uptake of nutrients, thus affecting human health. The aim of this study was to obtain knowledge on how variations in microstructure and texture of foods represented by four dairy products; (i) cheddar cheese, (ii) a homogenized cheddar cheese, (iii) a micellar casein and cream drink or (iv) a micellar casein and cream gel, all of identical nutrient ratios of protein : fat and calcium : fat, affect the in vitro digestibility kinetics of lipids. Rheology of the four dairy structures was measured at 10 °C and 37 °C before digestion, and during the gastric phase of in vitro digestion. During digestion cheddar cheese was most resistant to enzymatic and mechanical disintegration, followed by homogenized cheese, while both the drink and gel had low resistance and dissolved in the gastric juice. Particle size, fat droplet size and microstructure were assessed by light scattering and confocal microscopy during digestion. Significantly larger fat droplets were observed during digestion of the cheddar cheese sample. The release of free fatty acids during the initial intestinal digestion showed cheddar cheese to provide a significantly lower release than homogenized cheese, whereas the drink and gel both had significantly higher free fatty acid release. The results suggest that the cheese matrix resistance to degradation and its large fat droplets were responsible for a slower fat digestion.

Reductions in body weight and insulin resistance are not associated with changes in grey matter volume or cortical thickness during the PREVIEW study.

INTRODUCTION: The effect of changes in body weight or insulin resistance on grey matter volume and cortical thickness change are unclear. The present observational study assessed effects of an 8-week weight loss period (≥8% of body weight), and a subsequent 22-month weight maintenance period on grey matter volume and cortical thickness. METHODS: A total of 24 participants (12f/12 m; age 52.8 ±â€¯10.6 years) with overweight/obesity and pre-diabetes were recruited. T1-weighted magnetic resonance imaging was used to determine grey matter volume and cortical thickness at baseline, after the weight loss period and after a medium to high dietary protein weight maintenance period. RESULTS: At baseline, global grey matter volume was inversely associated with HOMA-IR, adjusted for sex and age (r = -0.42; p = .049). During the weight loss period participants decreased their BMI (32.1 ±â€¯3.3 to 28.1 ±â€¯2.8 kg/m2, p < .01), body-fat (41.6 ±â€¯6.4 to 35.0 ±â€¯8.0%, p < .01) and insulin resistance (HOMA-IR: 4.0 ±â€¯2.0 to 1.8 ±â€¯0.9, p < .01). During the 22-month weight maintenance period, these parameters gradually increased again (BMI: 29.3 ±â€¯3.8 kg/m2; body-fat: 37.8 ±â€¯9.3%; HOMA-IR: 2.9 ±â€¯1.4, p < .01). Global grey matter volume and cortical thickness did not change significantly during the weight loss or weight maintenance period. Changes in body weight, body-fat percentage or insulin sensitivity were not associated with changes in global grey matter volume. CONCLUSION: In conclusion, we confirmed that global grey brain matter volume was inversely associated with insulin resistance at baseline, yet an intervention yielding a decrease in insulin resistance did not lead to changes in global grey brain matter volume or cortical thickness. TRIAL REGISTRATION: The trial is registered with ClinicalTrials.gov, NCT01777893.

Whole flaxseeds but not sunflower seeds in rye bread reduce apparent digestibility of fat in healthy volunteers.

OBJECTIVE: The aim of this study was to measure the apparent digestibility of fat and the transit time upon addition of whole sunflower seeds (SU) or flaxseeds (FL) to rye breads consumed as part of a whole diet. METHOD: In a randomized crossover study, gross intake and faecal excretion of fat and energy were measured in 11 young healthy men aged 24.6+/-2.7 years. During each 7 days intervention periods, the subjects received a basal diet plus 300 g of one of four rye breads: (1) rye bread; (2) rye bread with SU; (3) rye bread with FL; (4) low extraction rate rye bread with SU and FL. Fat binding properties of rye breads (1) and (3) were determined by in vitro digestion. RESULTS: Addition of whole SU or FL to breads increased daily gross intake of fat and energy (P<0.001). The amounts of apparently digested fat (g/day) and energy were lowered when subjects consumed the SU or FL rye bread (P<0.001). The effect on energy digestibility of FL was more pronounced than that of SU. The in vitro fat digestibility of rye breads and whole diets show fat-binding properties of FL when compared to the rye bread diet (P<0.05). CONCLUSIONS: Enrichment of bread with whole FL does not appear to result in increased fat and energy intake when added to breads, but the results rather indicate an impairment of nutrient utilization.

Glucagon-like peptide 1 promotes satiety and suppresses energy intake in humans.

We examined the effect of intravenously infused glucagon-like peptide 1 (GLP-1) on subjective appetite sensations after an energy-fixed breakfast, and on spontaneous energy intake at an ad libitum lunch. 20 young, healthy, normal-weight men participated in a placebo-controlled, randomized, blinded, crossover study. Infusion (GLP-1, 50 pmol/ kg.h or saline) was started simultaneously with initiation of the test meals. Visual analogue scales were used to assess appetite sensations throughout the experiment and the palatability of the test meals. Blood was sampled throughout the day for analysis of plasma hormone and substrate levels. After the energy-fixed breakfast, GLP-1 infusion enhanced satiety and fullness compared with placebo (treatment effect: P < 0.03). Furthermore, spontaneous energy intake at the ad libitum lunch was reduced by 12% by GLP-1 infusion compared with saline (P = 0.002). Plasma GLP-1, insulin, glucagon, and blood glucose profiles were affected significantly by the treatment (P < 0.002). In conclusion, the results show that GLP-1 enhanced satiety and reduced energy intake and thus may play a physiological regulatory role in controlling appetite and energy intake in humans.

Overweight men's motivations and perceived barriers towards weight loss.

OBJECTIVE: To explore motivation and perceived barriers towards weight loss among Danish men. DESIGN: The study was of an explorative nature, using qualitative focus group interviews as a method. SETTING: Copenhagen, Denmark. SUBJECTS: Twenty-two overweight men, at the age of 25-44 years and motivated for weight loss, were recruited and distributed into four focus groups. The men were primarily unskilled workers. Overall 13 men participated and each group contained three or four participants. INTERVENTION: The interview guide was partly structured, partly unstructured and the themes of the interviews were motives and perceived barriers towards weight loss. RESULTS: Main barriers for losing weight appeared to be lack of motivation and the perception of the slimming diet. The men had a desire to have a lean appearance and avoid illness, but in all the interviews it appeared that the strongest motive for losing weight was a strong desire to become more effective and a greater asset for one's workplace. Overweight subjects were considered less effective and attractive for the labour market. CONCLUSION: This study indicates that if men from lower socioeconomic backgrounds are to be motivated to weight loss the focus should not be on leanness and good health but rather on increased effectiveness and performance, and the arena should include the working place. SPONSORSHIP: The Royal Veterinary and Agricultural University supplied the necessary equipment and conference rooms.

Biochemical control and toxicity for favorable- and intermediate-risk patients using real-time intraoperative inverse optimization prostate seed implant: Less is more!

PURPOSE: To report the biochemical control rate and clinical outcomes with real-time inverse planning (inverse optimization prostate seed implant [IO-PSI]) for favorable-risk (FR) and intermediate-risk (IR) prostate adenocarcinoma in a community practice setting. This analysis is an extended followup of our initial report, with favorable early biochemical control rate (biochemical nonevidence of disease) of 97% at 4 years. METHODS AND MATERIALS: Three hundred fifty-seven evaluable patients with FR and IR prostate cancer underwent real-time IO-PSI (iodine-125/145 Gy or palladium-103/120 Gy) between 2001 and 2013. RESULTS: With a median followup of 54 months (range, 24-110 months), the absolute biochemical failure free survival of disease was 96%. The 8-year actuarial probability of prostate-specific antigen failure-free survival for FR and IR cohorts was 92.4% and 87%, respectively. Late genitourinary and gastrointestinal toxicity remained low. Late Grade 2 and Grade 3 genitourinary toxicity was 19% and 1%, respectively. Late Grade 2 and 3 rectal bleeding rates were 1% and 0%, respectively. No difference in biochemical control was observed with preimplant short course androgen deprivation or between Gleason score 3 + 4 vs. 4 + 3 patients. No dosimetric parameter was predictive of biochemical failure. Patients with FR had a significantly decreased risk of failure (hazard ratio = 0.26; 95% confidence interval = 0.09-0.78; p = 0.02) compared with those with IR. Patients with a prostate-specific antigen nadir >0.4 ng/mL had an increased risk of failure (hazard ratio = 1.37; 95% confidence interval = 1.27-1.47; p < 0.0001). CONCLUSIONS: Our initial biochemical and clinical outcomes using real-time IO-PSI persisted with extended followup and support our original hypothesis for use of a reduced number of sources, needles, and total activity, suggesting that with IO, less is more.

Comparison of the 5-year outcome and morbidity of three-dimensional conformal radiotherapy versus transperineal permanent iodine-125 implantation for early-stage prostatic cancer.

PURPOSE: To compare the prostate-specific antigen (PSA) relapse-free survival outcome and incidence of late toxicity for patients with early-stage prostate cancer treated at a single institution with either three-dimensional conformal radiotherapy (3D-CRT) or transperineal permanent implantation (TPI) with iodine-125 seeds. MATERIALS AND METHODS: Patients with favorable-risk prostate cancer, defined as a pretreatment PSA of less than or equal to 10.0 ng/mL, Gleason score of 6 or lower, and stage less than or equal to T2b, were selected for this analysis. Between 1989 and 1996, 137 such patients were treated with 3D-CRT and 145 with TPI. The median ages of the 3D-CRT and TPI groups were 68 years and 64 years, respectively. The median dose of 3D-CRT was 70.2 Gy, and the median implant dose was 150 Gy. Prostate-specific antigen relapse was defined according to the American Society of Therapeutic Radiation Oncology Consensus Statement, and toxicity was graded according to the Radiation Therapy Oncology Group morbidity scoring scale. The median follow-up times for the 3D-CRT and TPI groups were 36 and 24 months, respectively. RESULTS: Eleven patients (8%) in the 3D-CRT group and 12 patients (8%) in the TPI group developed a biochemical relapse. The 5-year PSA relapse-free survival rates for the 3D-CRT and the TPI groups were 88% and 82%, respectively (P = .09). Protracted grade 2 urinary symptoms were more prevalent among patients treated with TPI compared with 3D-CRT. Grade 2 urinary toxicity, which was manifest after the implant and persisted for more than 1 year after this procedure, was observed in 45 patients (31%) in the TPI group. In these 45 patients, the median duration of grade 2 urinary symptoms was 23 months (range, 12 to 70 months). On the other hand, acute grade 2 urinary symptoms resolved within 4 to 6 weeks after completion of 3D-CRT, and the 5-year actuarial likelihood of late grade 2 urinary toxicity for the 3D-CRT group was only 8%. The 5-year actuarial likelihood of developing a urethral stricture (grade 3 urinary toxicity) for the 3D-CRT and TPI groups was 2% and 12%, respectively (P<.0002). Of 45 patients who developed grade 2 or higher urinary toxicity after TPI, the likelihood of resolution or significant improvement of these symptoms at 36 months from onset was 59%. The 5-year likelihood of grade 2 late rectal toxicity for the 3D-CRT and TPI patients was similar (6% and 11%, respectively; P = .97). No patient in either group developed grade 3 or higher late rectal toxicity. The 5-year likelihood of posttreatment erectile dysfunction among patients who were initially potent before therapy was 43% for the 3D-CRT group and 53% for the TPI group (P = .52). CONCLUSION: Both 3D-CRT and TPI are associated with an excellent PSA outcome for patients with early-stage prostate cancer. Urinary toxicities are more prevalent for the TPI group and subsequently resolve or improve in most patients. In addition to evaluating long-term follow-up, future comparisons will require detailed quality-of-life assessments to further determine the impact of these toxicities on the overall well-being and quality of life of the individual patient.

Should obese patients be counselled to follow a low-glycaemic index diet? No.

In diabetes research the glycaemic index (GI) of carbohydrates has long been recognized and a low GI is recommended. The same is now often the case in lipid research. Recently, a new debate has arisen around whether a low-GI diet should also be advocated for appetite- and long-term body weight control. A systematic review was performed of published human intervention studies comparing the effects of high- and low-GI foods or diets on appetite, food intake, energy expenditure and body weight. In a total of 31 short-term studies (< 1 d), low-GI foods were associated with greater satiety or reduced hunger in 15 studies, whereas reduced satiety or no differences were seen in 16 other studies. Low-GI foods reduced ad libitum food intake in seven studies, but not in eight other studies. In 20 longer-term studies (< 6 months), a weight loss on a low-GI diet was seen in four and on a high-GI diet in two, with no difference recorded in 14. The average weight loss was 1.5 kg on a low-GI diet and 1.6 kg on a high-GI diet. To conclude, there is no evidence at present that low-GI foods are superior to high-GI foods in regard to long-term body weight control. However, the ideal long-term study where ad libitum intake and fluctuations in body weight are permitted, and the diets are similar in all aspects except GI, has not yet been performed.

Diurnal metabolic profiles after 14 d of an ad libitum high-starch, high-sucrose, or high-fat diet in normal-weight never-obese and postobese women.

BACKGROUND: The influence of the amount and type of carbohydrates in the diet on risk factors for obesity, diabetes, and cardiovascular disease remains unclear. OBJECTIVE: We investigated the effects of 2 low-fat diets (high-sucrose and high-starch) and a high-fat diet on glycemia, lipidemia, and hormonal responses in never-obese and postobese women. DESIGN: Eighteen normal-weight women (8 postobese and 10 never-obese) consumed 3 ad libitum diets (high-fat, high-starch, and high-sucrose) for 14 d each. On day 15, we measured fasting and postprandial glucose, lactate, insulin, triacylglycerol, nonesterified fatty acids (NEFA), glycerol, glucagon, glucose-dependent insulinotropic polypeptide, and glucagon-like peptide 1. RESULTS: The high-sucrose diet induced significantly lower total areas under the curve (AUCs) for glucose and NEFA and a significantly higher lactate AUC than did the high-fat and high-starch diets; there were no significant differences in the insulin AUCs. The triacylglycerol AUC was greater with the high-fat and high-sucrose diets than with the high-starch diet. Gastrointestinal hormone concentrations differed between diets, but not between the 2 subject groups. Comparisons between subject groups for all diets combined showed lower relative insulin resistance and lower AUCs for glucose, insulin, and triacylglycerol in the postobese group. CONCLUSIONS: High-starch and high-sucrose diets had no adverse effects on postprandial glycemia, insulinemia, or lipidemia compared with a high-fat diet. A sucrose-rich diet may improve glucose metabolism, but may have an adverse effect on lipidemia, compared with a starch-rich diet. Postobese women seemed to be more insulin-sensitive and more efficient at storing triacylglycerol than were never-obese women, regardless of dietary composition.

Low resting metabolic rate in subjects predisposed to obesity: a role for thyroid status.

A low resting metabolic rate (RMR) for a given body composition has been identified as a risk factor for weight gain and obesity, and has also been reported in formerly obese individuals with the genetic predisposition for obesity. The possible role of thyroid hormone in low RMR was studied in a large sample of postobese women. RMR was measured by indirect calorimetry in 28 weight-stable postobese women with a family history of obesity (PO group) and in a control group of 28 nonobese women closely matched for age, fat mass, and fat-free mass. RMR was 8% lower in the PO than in the control group [[symbol: see text]; 95% Cl:5856 (5520, 6214) compared with 6408 kJ/d (6096, 6768 kJ/d), P < 0.02], and the group difference remained unchanged after fat-free mass and fat mass were adjusted for (552 kJ/d, P < 0.015). The PO group had lower plasma free triiodothyronine [2.4 (1.9, 3.0) compared with 3.4 pmol/L (2.9, 3.9 pmol/L), P < 0.01], whereas plasma androstenedione only tended to be lower in the PO than in the control group. Adjustment for differences in androstenedione did not reduce the difference in RMR, whereas adjustment for differences in plasma free triiodothyronine eliminated the group difference (96 kJ/d, P = 0.59). The present study shows that RMR for a given body composition is lower among postobese than among matched never-obese control subjects. Statistically, the lower plasma free triiodothyronine concentrations of the postobese subjects could explain their lower RMRs, but it remains to be established whether these findings are causally related.

The effect of raw potato starch on energy expenditure and substrate oxidation.

Because resistant starch (RS) is not absorbed as glucose in the small intestine of healthy humans, postprandial thermogenesis should be lower after the intake of RS as compared with digestible starch. To evaluate this hypothesis, we measured 5-h postprandial thermogenesis and substrate oxidation by indirect calorimetry after ingestion of 50 g pregelatinized (0% RS) and 50 g raw potato starch (54% type II RS) in 15 healthy, normal-weight young males. The subjects consumed each starch (mixed in diluted fruit syrup) twice on separate days and in random order. RS intake was followed by lower thermogenesis (46.5 +/- 13.1 compared with 115.4 +/- 10.4 kJ/5 h; P = 0.008), lower glucose oxidation (P < 0.0005), and greater fat oxidation (P = 0.013) than was pregelatinized starch consumption. Our results suggest that RS has no thermogenic effect and that its presence does not influence the size of the thermic response to digestible starch.

Obesity as an adaptation to a high-fat diet: evidence from a cross-sectional study.

Expansion of the fat stores has been proposed as a prerequisite for increasing fat oxidation in response to a high-fat diet in individuals with a predisposition to obesity. In a cross-sectional design we measured 24-h substrate oxidations on a standardized diet in 38 overweight or obese and 35 nonobese women. Fat oxidation (g/d) was mainly a function of total energy requirements (r = 0.71, P < 0.0001). To account for this we used for further analysis oxidative fat energy (%), a counterpart to dietary fat energy (%). After differences in fat energy of consumed food (%), age, and 24-h energy balance were adjusted for, obese women had higher oxidative fat energy than did nonobese women [40.2% (37.8-42.6) vs 36.0% (33.6-38.5), P < 0.02]. Adjusted oxidative fat energy (%) increased with increasing size of fat mass (r = 0.31, P < 0.01). This relation suggests that a 10-kg change in fat mass may be caused by a change in dietary fat energy of > or = 1.6% (0.4-2.7%). The study supports the concept that in susceptible individuals the expansion of fat stores is a prerequisite to increase the oxidative fat energy to an amount commensurate with a high percentage of dietary fat energy.

Resistant starch: the effect on postprandial glycemia, hormonal response, and satiety.

The effect of resistant starch (RS) on postprandial plasma concentrations of glucose, lipids, and hormones, and on subjective satiety and palatability ratings was investigated in 10 healthy, normal-weight, young males. The test meals consisted of 50 g pregelatinized starch (0% RS) (S) or 50 g raw potato starch (54% RS) (R) together with 500 g artificially sweetened syrup. After the R meal postprandial plasma concentrations of glucose, lactate, insulin, gastric inhibitory polypeptide (GIP), glucagon-like peptide-1, and epinephrine were significantly lower compared with after the S meal. Moreover, subjective scores for satiety and fullness were significantly lower after the R meal than after the S meal. Differences in GIP, texture, and palatability may have been involved in these findings. In conclusion, the replacement of digestible starch with RS resulted in significant reductions in postprandial glycemia and insulinemia, and in the subjective sensations of satiety.

Acetylation of or beta-cyclodextrin addition to potato beneficial effect on glucose metabolism and appetite sensations.

Functional foods are gaining more and more interest from health scientists. One way to improve the nutritional properties of foods may be to modify the starch component, often included to stabilize the food product. In this study two chemically modified starches-a 1-2% acetylated potato starch and a starch enriched with 2% beta-cyclodextrin-and a native, unmodified potato starch (control) were investigated with regard to 6-h energy expenditure, substrate metabolism, hormone concentrations, and subjective appetite sensations. Subjects were 11 healthy, normal-weight, young men. The starch (50 g) was prepared as a pudding with fruit sauce and whipped cream (3180 kJ, 49% of energy from carbohydrate, and 40% of energy from fat). The meal was given in the morning after a 2-d carbohydrate-rich, weight-maintenance diet. After the modified-starch meals, response patterns for plasma glucose (P < 0.01), insulin (P < 0.05); gastric inhibitory polypeptide (P < 0.05), subjective satiety (P < 0.05), and fullness (P = 0.06) were significantly different from response patterns after the meal with the control starch. Thus, a flattening of the glucose curve, a lower insulin and gastric inhibitory polypeptide response, and higher fullness ratings were observed after the meal with the beta-cyclodextrin starch. Satiety ratings were higher after both meals with modified starch than after the meal with the control starch. In conclusion, a minor modification insulinemic (1-2%) of native potato starch improved the glycemia, insulinemic, and satiating properties of a meal. This was especially true for the beta-cyclodextrin-enriched starch. Slower gastric-emptying rate or delayed intestinal absorption of the modified starch may explain the observed differences.

Decreased postprandial thermogenesis and fat oxidation but increased fullness after a high-fiber meal compared with a low-fiber meal.

The effect of a high-fiber (4.7 g/MJ) and an isoenergetic low-fiber (1.7 g/MJ) meal on 6-h postprandial thermogenesis, substrate metabolism, hormones, and satiety was investigated in 10 healthy, normal-weight male subjects. Diet-induced thermogenesis (DIT) was significantly reduced after the high-fiber meal (416.4 +/- 28.6 kJ/6 h) compared with the low-fiber meal (498.5 +/- 23.1 kJ/6 h; ANOVA: P < 0.0001), as was postprandial fat oxidation (P < 0.0001). The difference in DIT was correlated with the different palatability of the test meal (r = 0.89, P < 0.01). No differences were observed in plasma concentrations of glucose, insulin, norepinephrine, epinephrine, or gastrointestinal hormones, but C-peptide increased less (P < 0.05) and nonesterified fatty acids decreased more (P < 0.05) after the high-fiber meal. Finally, fullness was increased and desire to eat decreased after the high-fiber meal (P < 0.0001). In conclusion, a high-fiber meal decreased DIT and fat oxidation but increased fullness compared with a low-fiber meal.