Effects Of Macronutrient Content Research Articles

The effect of a high fat and high carbohydrate meal on satiety hormone response and subjective hunger in humans

The effect of macronutrient content on postprandial hormonal release and subjective hunger was investigated in 10 male subjects. In random order, subjects either continued an overnight fast or were given a meal high in carbohydrate (CHO) or fat Blood samples and subjective hunger ratings were recorded 30 minutes preprandial and at 30, 90, and 210 minutes postprandial. Following the CHO meal, postprandial levels of insulin, C-peptide, and amylin were significantly greater (all: P<0.001) and GLP-1 had a non-significant increase when compared to fat. Following the fat meal, glucagon and GLP-1 increased significantly compared to the CHO meal (both: P<0.001). Whilst hormonal responses were different following the CHO and fat meal, postprandial subjective hunger ratings did not significantly differ. In both meal protocols, “fullness” was associated with plasma GLP-1 (r = 0.84, P<0.01), glucagon (r = −0.80, P<0.01), and C-peptide (r = −0.65, P<0.05). “Hunger” was related to GLP-1 (r = − 0.84, P<0.01) and C-peptide (r = 0.77, P<0.01), whereas “desire to eat” was solely correlated to GLP-1 (r = −0.85, P<0.01)). In conclusion, although a single meal high in CHO or fat produced differing postprandial hormonal responses, subjective hunger was not affected. It appears that there are varying degrees of hormonal action that can influence subjective hunger, suggesting that when different macronutrients are consumed distinct combinations of hormones are released. However, these varying hormonal combinations seem to affect subjective hunger similarly. Funded by AHFMR and CIHR.

Popular diets: a scientific review.

Introduction Weight loss is a major concern for the US population. Surveys consistently show that most adults are trying to lose or maintain weight (1). Nevertheless, the prevalence of overweight and obesity has increased steadily over the past 30 years. Currently, 50% of all adult Americans are considered overweight or obese (2,3). These numbers have serious public health implications. Excess weight is associated with increased mortality (4) and morbidity (5). It is associated with cardiovascular disease, type 2 diabetes, hypertension, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and some types of cancer (6,7). Most people who are trying to lose weight are not using the recommended combination of reducing caloric intake and increasing physical activity (1). Although over 70% of persons reported using each of the following strategies at least once in 4 years, increased exercise (82.2%), decreased fat intake (78.7%), reduced food amount (78.2%,) and reduced calories (73.2%), the duration of any one of these behaviors was brief. Even the most common behaviors were used only 20% of the time (8). Obesity-related conditions are significantly improved with modest weight loss of 5% to 10%, even when many patients remain considerably overweight (6). The Institute of Medicine (9) defined successful long-term weight loss as a 5% reduction in initial body weight (IBW) that is maintained for at least 1 year. Yet data suggest that such losses are not consistent with patients’ goals and expectations. Foster (10) reported that in obese women (mean body mass index [BMI] of 36.3 6 4.3) goal weights targeted, on average, a 32% reduction in IBW, implying expectations that are unrealistic for even the best available treatments. Interestingly, the most important factors that influenced the selection of goal weights were appearance and physical comfort rather than change in medical condition or weight suggested by a doctor or health care professional. Is it any wonder that overweight individuals are willing to try any new diet that promises quick, dramatic results more in line with their desired goals and expectations than with what good science supports? The proliferation of diet books is nothing short of phenomenal. A search of books on Amazon.com using the key words “weight loss” revealed 1214 matches. Of the top 50 best-selling diet books, 58% were published in 1999 or 2000 and 88% were published since 1997. Many of the top 20 best sellers at Amazon.com promote some form of carbohydrate (CHO) restriction (e.g., Dr. Atkins’ New Diet Revolution, The Carbohydrate Addict’s Diet, Protein Power, Lauri’s Low-Carb Cookbook). This dietary advice is counter to that promulgated by governmental agencies (US Department of Agriculture [USDA]/Department of Health and Human Services, National Institutes of Health) and nongovernmental organizations (American Dietetic Association, American Heart Association, American Diabetes Association, American Cancer Society, and Shape Up America!). What is really known about popular diets? Is the information scientifically sound? Are popular diets effective for weight loss and/or weight maintenance? What is the effect, if any, on composition of weight loss (fat vs. lean body mass), micronutrient (vitamin and mineral) status, metabolic parameters (e.g., blood glucose, insulin sensitivity, blood pressure, lipid levels, uric acid, and ketone bodies)? Do they affect hunger and appetite, psychological well-being, and reduction of risk for chronic disease (e.g., coronary heart disease, diabetes, and osteoporosis)? What are the effects of these diets on insulin and leptin, long-term hormonal regulators of energy intake and expenditure? The objective of this article is to review the scientific literature on various types of popular diets based on their macronutrient composition in an attempt to answer these questions (see Appendix for diet summaries). Address correspondence to Dr. Janet King, U.S. Department of Agriculture, Agricultural Research Service, Western Human Nutrition Research Center, University of California, 1 Shield Avenue, Building Surge IV, Room 213, Davis, CA 95616. E-mail: jking@ whnrc.usda.gov Copyright © 2001 NAASO

Effects of macronutrient content and energy density of snacks consumed in a satiety state on the onset of the next meal

We examined the effects of nutrient composition of a 1MJ afternoon snack, consumed in a satiety state, on the spontaneous onset of the next meal in 11 young male subjects deprived of any temporal cues. All subjects attended four experimental sessions scheduled 2 weeks apart. The first, baseline, session served to establish: (1) the subjects' ad libitum lunch intake, (2) the latency of the spontaneous request for dinner following lunch, (3) ad libitum food intake at dinner. Lunches provided during the next three sessions were based on baseline lunch intakes. During the following three sessions, conducted in counterbalanced order, subjects were given a high-fat (58% of energy from fat), a high-protein (77%) or a high-carbohydrate (84%) snack to be consumed 240min after the beginning of lunch. Latency to dinner and the amount of energy consumed at dinner were two dependent variables.Consumption of a high-protein snack delayed the request for dinner by 60min. In contrast, high-fat snack delayed dinner request by 25min, whereas high-carbohydrate snack delayed dinner request by 34min. Snack composition had no impact on energy or macronutrient intakes during dinner.