Nondigestible Carbohydrates Affect Metabolic Health and Gut Microbiota in Overweight Adults after Weight Loss.

BACKGROUND: The composition of diets consumed following weight loss (WL) can have a significant impact on satiety and metabolic health. OBJECTIVE: This study was designed to test the effects of including a nondigestible carbohydrate to achieve weight maintenance (WM) following a period of WL. METHODS: Nineteen volunteers [11 females and 8 males, aged 20-62 y; BMI (kg/m2): 27-42] consumed a 3-d maintenance diet (15%:30%:55%), followed by a 21-d WL diet (WL; 30%:30%:40%), followed by 2 randomized 10-d WM diets (20%:30%:50% of energy from protein:fat:carbohydrate) containing either resistant starch type 3 (RS-WM; 22 or 26 g/d for females and males, respectively) or no RS (C-WM) in a within-subject crossover design without washout periods. The primary outcome, WM after WL, was analyzed by body weight. Secondary outcomes of fecal microbiota composition and microbial metabolite concentrations and gut hormones were analyzed in fecal samples and blood plasma, respectively. All outcomes were assessed at the end of each dietary period. RESULTS: Body weight was similar after the RS-WM and C-WM diets (90.7 and 90.8 kg, respectively), with no difference in subjectively rated appetite. During the WL diet period plasma ghrelin increased by 36% (P < 0.001), glucose-dependent insulinotropic polypeptide (GIP) decreased by 33% (P < 0.001), and insulin decreased by 46% (P < 0.001), but no significant differences were observed during the RS-WM and C-WM diet periods. Fasting blood glucose was lower after the RS-WM diet (5.59 ± 0.31 mmol/L) than after the C-WM diet [5.75 ± 0.49 mmol/L; P = 0.015; standard error of the difference between the means (SED): 0.09]. Dietary treatments influenced the fecal microbiota composition (R2 = 0.054, P = 0.031) but not diversity. CONCLUSIONS: The metabolic benefits, for overweight adults, from WL were maintained through a subsequent WM diet with higher total carbohydrate intake. Inclusion of resistant starch in the WM diet altered gut microbiota composition positively and resulted in lower fasting glucose compared with the control, with no apparent change in appetite. This trial was registered at clinicaltrials.gov as NCT01724411.

A workshop on 'Dietary Sweetness-Is It an Issue?'

This report summarises a workshop convened by ILSI Europe on 3 and 4 April 2017 to discuss the issue of dietary sweetness. The objectives were to understand the roles of sweetness in the diet, establish whether exposure to sweetness affects diet quality and energy intake, and consider whether sweetness per se affects health. Although there may be evidence for tracking of intake of some sweet components of the diet through childhood, evidence for tracking of whole diet sweetness, or through other stages of maturity are lacking. The evidence to date does not support adverse effects of sweetness on diet quality or energy intake, except where sweet food choices increase intake of free sugars. There is some evidence for improvements in diet quality and reduced energy intake where sweetness without calories replaces sweetness with calories. There is a need to understand the physiological and metabolic relevance of sweet taste receptors on the tongue, in the gut and elsewhere in the body, as well as possible differentiation in the effects of sustained consumption of individual sweeteners. Despite a plethora of studies, there is no consistent evidence for an association of sweetness sensitivity/preference with obesity or type 2 diabetes. A multifaceted integrated approach, characterising nutritive and sensory aspects of the whole diet or dietary patterns, may be more valuable in providing contextual insight. The outcomes of the workshop could be used as a scientific basis to inform the expert community and create more useful dialogue among health care professionals.

The effects of the combination of egg and fiber on appetite, glycemic response and food intake in normal weight adults - a randomized, controlled, crossover trial.

This study evaluated appetite and glycemic effects of egg-based breakfasts, containing high and moderate protein (30 g protein and 20 g protein +7 g fiber, respectively) compared to a low-protein cereal breakfast (10 g protein) examined in healthy adults (N = 48; age 24 ± 1 yr; BMI 23 ± 1 kg/m(2); mean ± SE). Meals provided 390 kcal/serving and equal fat content. Food intake was measured at an ad libitum lunch meal and blood glucose response was measured. Visual analog scales (VAS) were used to assess hunger, satisfaction, fullness, and prospective food intake. The egg-based breakfast meal with high protein produced greater overall satiety (p < 0.0001), and both high protein and moderate protein with fiber egg-based breakfasts reduced postprandial glycemic response (p < 0.005) and food intake (p < 0.05) at subsequent meal (by 135 kcal and 69 kcal; effect sizes 0.44 and 0.23, respectively) compared to a cereal-based breakfast with low protein and fiber.

The Effects of a Beef-Based Meal Compared to a Calorie Matched Bean-Based Meal on Appetite and Food Intake.

Protein and fiber have strong satiety-inducing potential. Beef is a high quality, protein-rich food. Beans contain moderate levels of protein as well as fiber. To determine the effects of a high protein meal (beef) compared to a moderate protein, high fiber meal (beans) on subjective appetite and energy intake at a subsequent meal twenty-eight adults, 14 men (ages 24 ± 5 y, BMI 23 ± 2 kg/m(2) ) and 14 women (ages 25 ± 5 y, BMI 22 ± 2 kg/m(2) ) consumed 2 test lunches containing a "meatloaf" made from either beef or beans. The beef meal provided 26 g of protein and 3 g of fiber while the bean meal provided 17 g of protein and 12 g of fiber. An ad libitum snack was given 3 h after the test meal. Visual analogue scales were used to assess hunger, satiety, fullness, and prospective food intake. Gastrointestinal (GI) tolerance was assessed over 24 h. No difference between the beef and bean was observed for appetite ratings over 3 h, food intake at the subsequent meal (632 ± 75 kcal compared with 611 ± 75 kcal, respectively), or sum of GI score (2.2 ± 0.5 compared with 2.9 ± 0.5, respectively). Gas and bloating were reported more often after the bean meal than the beef meal (2.0 ± 0.4 compared with 1.3 ± 0.4, P value 0.057). A beef-based meal with high protein and a bean-based meal with moderate protein and high fiber produced similar satiety, while the bean-based meal resulting in higher, yet moderate, gas and bloating.

Gastrointestinal tolerance of chicory inulin products.

BACKGROUND: The use of inulin in foods as a fiber source has increased recently. Consumption of inulin products can cause gastrointestinal (GI) distress. Acceptable intakes of inulin need to be determined. OBJECTIVE: To determine the GI tolerance of two inulin fibers, shorter chain length oligofructose and native inulin, at 5- and 10-g doses compared to a placebo. DESIGN: A randomized, double-blind, controlled, crossover design that included a phone screening and five visits for breakfast fiber challenges consisting of a bagel, cream cheese, and orange juice. SUBJECTS/SETTING: Twenty-six healthy men and women ages 18 to 60 years participated in the study. Healthy subjects with no history of GI conditions consumed diets with typical amounts of fiber. MAIN OUTCOME MEASURES: GI tolerance was calculated as the sum of scores on seven GI tolerance domains via questionnaire administered at t=0, 2, 4, 24, and 48 hours following fiber challenge. STATISTICAL ANALYSES PERFORMED: A mixed effects linear model was used to compare the tolerance scores among the five fiber challenges. RESULTS: The two inulin fibers tended to increase GI symptoms mildly. Most frequently reported symptoms were flatulence followed by bloating. The 10-g dose of oligofructose substantially increased GI symptoms compared to control. CONCLUSIONS: Doses up to 10 g/day of native inulin and up to 5 g/day of oligofructose were well-tolerated in healthy, young adults.