Impact of physical activity level and dietary fat content on passive overconsumption of energy in non-obese adults

Background: Passive overconsumption is the increase in energy intake driven by the high-fat energy-dense food environment. This can be explained in part because dietary fat has a weaker effect on satiation (i.e. process that terminates feeding). Habitually active individuals show improved satiety (i.e. process involved in post-meal suppression of hunger) but any improvement in satiation is unknown. Here we examined whether habitual physical activity mitigates passive overconsumption through enhanced satiation in response to a high-fat meal. Methods: Twenty-one non-obese individuals with high levels of physical activity (HiPA) and 19 individuals with low levels of physical activity (LoPA) matched for body mass index (mean = 22.8 kg/m2) were recruited. Passive overconsumption was assessed by comparing ad libitum energy intake from covertly manipulated high-fat (HFAT; 50% fat) or high-carbohydrate (HCHO; 70% carbohydrate) meals in a randomized crossover design. Habitual physical activity was assessed using SenseWear accelerometers (SWA). Body composition, resting metabolic rate, eating behaviour traits, fasting appetite-related peptides and hedonic food reward were also measured. Results: In the whole sample, passive overconsumption was observed with greater energy intake at HFAT compared to HCHO (p  0.05). SWA confirmed that HiPA were more active than LoPA (p  0.05 for all). Conclusions: Non-obese individuals with high or low physical activity levels but matched for BMI showed similar susceptibility to passive overconsumption when consuming an ad libitum high-fat compared to a high-carbohydrate meal. This occurred despite increased total daily energy expenditure and improved body composition in HiPA. Greater differences in body composition and/or physical activity levels may be required to impact on satiation

Nutritional strategies of high level natural bodybuilders during competition preparation

Background Competitive bodybuilders employ a combination of resistance training, cardiovascular exercise, calorie reduction, supplementation regimes and peaking strategies in order to lose fat mass and maintain fat free mass. Although recommendations exist for contest preparation, applied research is limited and data on the contest preparation regimes of bodybuilders are restricted to case studies or small cohorts. Moreover, the influence of different nutritional strategies on competitive outcome is unknown. Methods Fifty-one competitors (35 male and 16 female) volunteered to take part in this project. The British Natural Bodybuilding Federation (BNBF) runs an annual national competition for high level bodybuilders; competitors must qualify by winning at a qualifying events or may be invited at the judge’s discretion. Competitors are subject to stringent drug testing and have to undergo a polygraph test. Study of this cohort provides an opportunity to examine the dietary practices of high level natural bodybuilders. We report the results of a cross-sectional study of bodybuilders competing at the BNBF finals. Volunteers completed a 34-item questionnaire assessing diet at three time points. At each time point participants recorded food intake over a 24-h period in grams and/or portions. Competitors were categorised according to contest placing. A “placed” competitor finished in the top 5, and a “Non-placed” (DNP) competitor finished outside the top 5. Nutrient analysis was performed using Nutritics software. Repeated measures ANOVA and effect sizes (Cohen’s d) were used to test if nutrient intake changed over time and if placing was associated with intake. Results Mean preparation time for a competitor was 22 ± 9 weeks. Nutrient intake of bodybuilders reflected a high-protein, high-carbohydrate, low-fat diet. Total carbohydrate, protein and fat intakes decreased over time in both male and female cohorts (P < 0.05). Placed male competitors had a greater carbohydrate intake at the start of contest preparation (5.1 vs 3.7 g/kg BW) than DNP competitors (d = 1.02, 95% CI [0.22, 1.80]). Conclusions Greater carbohydrate intake in the placed competitors could theoretically have contributed towards greater maintenance of muscle mass during competition preparation compared to DNP competitors. These findings require corroboration, but will likely be of interest to bodybuilders and coaches. Keywords BodybuildersCaloriesCompetitionContest preparationDietingEnergy restrictionNaturalNutritionSupplementationPhysiqu

Bath Breakfast Project (BBP) - Examining the role of extended daily fasting in human energy balance and associated health outcomes: Study protocol for a randomised controlled trial [ISRCTN31521726]

<p>Abstract</p> <p>Background</p> <p>Current guidance regarding the role of daily breakfast in human health is largely grounded in cross-sectional observations. However, the causal nature of these relationships has not been fully explored and what limited information is emerging from controlled laboratory-based experiments appears inconsistent with much existing data. Further progress in our understanding therefore requires a direct examination of how daily breakfast impacts human health under free-living conditions.</p> <p>Methods/Design</p> <p>The Bath Breakfast Project (BBP) is a randomised controlled trial comparing the effects of daily breakfast consumption relative to extended fasting on energy balance and human health. Approximately 70 men and women will undergo extensive laboratory-based assessments of their acute metabolic responses under fasted and post-prandial conditions, to include: resting metabolic rate, substrate oxidation, dietary-induced thermogenesis and systemic concentrations of key metabolites/hormones. Physiological and psychological indices of appetite will also be monitored both over the first few hours of the day (i.e. whether fed or fasted) and also following a standardised test lunch used to assess voluntary energy intake under controlled conditions. Baseline measurements of participants' anthropometric characteristics (e.g. DEXA) will be recorded prior to intervention, along with an oral glucose tolerance test and acquisition of adipose tissue samples to determine expression of key genes and estimates of tissue-specific insulin action. Participants will then be randomly assigned either to a group prescribed an energy intake of ≥3000 kJ before 1100 each day or a group to extend their overnight fast by abstaining from ingestion of energy-providing nutrients until 1200 each day, with all laboratory-based measurements followed-up 6 weeks later. Free-living assessments of energy intake (via direct weighed food diaries) and energy expenditure (via combined heart-rate/accelerometry) will be made during the first and last week of intervention, with continuous glucose monitors worn both to document chronic glycaemic responses to the intervention and to verify compliance.</p> <p>Trial registration</p> <p>Current Controlled Trials <a href="http://www.controlled-trials.com/ISRCTN31521726">ISRCTN31521726</a>.</p

Habitual meal frequency and energy intake regulation in partially temporally isolated men

Department of Human Biology, University of Maastricht, Maastricht, The Netherlands. [email protected] OBJECTIVE: Assessment of a possible relationship between habitual as well as manipulated meal frequency, blood glucose pattern, macronutrient- and energy intake (EI), and energy intake regulation in partially temporally isolated men. DESIGN: A partially temporally isolated within-subject design assessing energy intake regulation in spite of intervention. Intervention consisted of manipulating meal frequency by offering iso-energetic (1 MJ) preloads high in fat or carbohydrate (CHO), with the same energy density. We have previously shown that after a high-CHO preload, inter-meal-interval was 1 h, while after a high-fat preload intermeal-interval was 2 h. SUBJECTS: Twenty healthy young (18-31 y) normal weight (body mass index (BMI): 22.8+/-1.9 kg/m(2)) men. MEASUREMENTS: On two separate days, each after a different preload: subsequent subjects' responses to the preload, eg manipulated meal frequency; continuous blood glucose levels and blood glucose patterns: macronutrient composition of food intake; EI; appetite ratings; and taste perception. From controlled 3-day food intake diaries: habitual meal frequency; EI; and macronutrient-intake. RESULTS: Accuracy of energy intake regulation is expressed as minimizing the difference in energy intake, despite intervention. The difference in 24 h EI on the two test days after the preloads (r(2)=0.56; P<0.001) was a function of habitual meal frequency. Variation in energy intake was primarily explained by habitual meal frequency (r(2)=0.76; P<0.0001). Adding macronutrient composition and number of blood glucose declines to this increased the explained variation to 86 and 96%, respectively. Percentage energy from CHO or from fat explained the variation in habitual meal frequency (r(2)=0.84; P<0.0001). Adding the total number of blood-glucose declines to this increased the explained variation to 88%, and adding average baseline blood glucose levels, sweetness perception and hunger suppression during preload consumption increased the explained variation to 91%. Manipulated meal frequency was related to habitual meal frequency (r(2)=0.86; P<0.0001) and was a function of the number of transient and dynamic blood glucose declines (r(2)=0.74; P<0.0001). CONCLUSION: Habitual meal frequency is of greater significance in energy intake regulation in healthy young men than manipulated meal frequency. Healthy young men with a high habitual meal frequency showed lower 24 h EI, and a smaller difference in EI after macronutrient specific preloads, compared to those with a low habitual meal frequency, thus showing a more accurate energy intake regulation. Habitual meal frequency is based upon a cluster of related factors including macronutrient composition of the food, sweetness perception, hunger suppression, blood glucose declines and average baseline blood glucose levels. Publication Types: Clinical Trial Randomized Controlled Tria

Use of artificial sweeteners and fat-modified foods in weight loss maintainers and always-normal weight individuals

Objective: The purpose of this study was to compare the dietary strategies, and use of fat- and sugar-modified foods and beverages in a weight loss maintainer group (WLM) and an always-normal weight group (NW). Subjects: WLM (N=172) had maintained ≥10% weight loss for 11.5 years, and had a body mass index (BMI) of 22.0 kg m-2. NW (N=131) had a BMI of 21.3 kg m-2 and no history of being overweight. Three, 24-h recalls on random, non-consecutive days were used to assess dietary intake. Results: WLM reported consuming a diet that was lower in fat (28.7 vs 32.6%, PConclusions: These findings suggest that WLM use more dietary strategies to accomplish their weight loss maintenance, including greater restriction on fat intake, use of fat- and sugar-modified foods, reduced consumption of sugar-sweetened beverages and increased consumption of artificially sweetened beverages. Ways to promote the use of fat-modified foods and artificial sweeteners merits further research in both prevention- and treatment-controlled trials

Gender differences in physical and psychological stress responses among college judoists undergoing weight reduction

Gender-related differences in anthropometry, blood biochemistry, psychological parameters, and energy intake during prematch weight reduction were studied in 22 men and 7 women college judoists who lost weight by combining judo training, restricting food and fluid, and sweating. Body weight (BW) decreased significantly by 2.2±1.4 kg in men and 2.0±1.4 kg in women 2 weeks after weight reduction started — not significandy different. Body fat, relative body fat and total energy intake also decreased significandy in both groups 2 weeks after weight reduction started. Lean body mass decreased significandy 2 weeks after weight reduction started only in men. Men had significantly decreased blood lipids, immunoglobulins, complements, hematocrit, white blood cell count, and serum electrolytes, and significant increases in blood uric nitrogen, creatinine, and hemoglobin, while women showed no such changes. The score for vigor in the Profile of Mood States (POMS) decreased in both groups 2 weeks after weight reduction started, but with no statistically gender difference. In women, scores for anxiety in the State-Trait Anxiety Inventory (STAI) and confusion in POMS increased significandy. Although the men and women had the same BW reduction, significant physical stress response was seen only in men, and psychological stress due to weight reduction and mental pressure of an upcoming competition were seen more in women