Changes In Macronutrient Composition Research Articles

FRI391 A Metabolomics Analysis Of Moderate Energy Restriction In Healthy Lean Women

Abstract Disclosure: L. Levine: None. K. Overdahl: None. S. Molsberry: None. S. Shekhar: None. A. Jarmusch: None. J.E. Hall: None. Introduction: Metabolomics can elucidate metabolic responses to dietary interventions and has been used in energy restriction studies, primarily in overweight/obese men and women. Although the menstrual cycle affects the metabolome, most dietary intervention studies have not controlled for menstrual cycle phase, nor have they examined the effect of moderate, short-term energy restriction on the metabolic profile of healthy, normal-weight women. Objective: To characterize metabolomic changes in response to a 55% reduction in dietary intake during the early follicular phase of the menstrual cycle. Methods: Study participants included 19 healthy women aged 18-28 years who were of normal BMI and fitness, not restricting nutritional intake and with biochemically confirmed regular ovulatory menstrual cycles. Participants underwent 5-day dietary interventions in the early follicular phase of two menstrual cycles. The first diet consisted of neutral energy availability (NEA; 45 kcal/kg*lean body mass/day) and the second of deficient energy availability (DEA; 20 kcal/kg*lean body mass/day) without changes in macronutrient composition. On the 5th day of each diet, serum was collected at ∼8am following an overnight fast, and immediately before and every 10 minutes for 60 minutes after the consumption of a standardized isocaloric snack at ∼4pm. Untargeted metabolomic profiling was performed using ultra-high performance liquid chromatography/mass spectroscopy. Univariate statistics were performed on all metabolites, using t-tests with Benjamini-Hochberg false discovery rate adjusted p-values to account for multiple testing (p-value ≤ 0.05). Log2-fold change was calculated for all chemical features. Results: At baseline, participants had a weight of 61.9±2.75 kg (mean±SEM), BMI of 23.96±0.69 kg/m2 (mean±SEM), and percent body fat of 28.01±1.61% (mean±SEM). DEA resulted in a 1.25±0.13 kg (mean±SEM) decrease in body weight (p<0.01). While few statistically significant differences were present between fasted NEA and DEA samples, numerous chemical features were significantly upregulated in DEA post-snack samples. Specifically, 11 carnitines, 7 phosphocholines, and 8 fatty acids or fatty acid intermediates exhibited a log2fold change of 0.5 or higher (>40% increase; p ≤ 0.05) in post-snack DEA samples compared to NEA samples. Conclusion: These results strongly suggest that following isocaloric intake, moderate energy restriction in normal-weight, healthy women is associated not only with the use of fat as an energy source, but also with cellular membrane breakdown. Presentation: Friday, June 16, 2023

Macronutrient Recommendations for Remission and Prevention of Diabetes in Asian Indians Based on a Data-Driven Optimization Model: The ICMR-INDIAB National Study.

To derive macronutrient recommendations for remission and prevention of type 2 diabetes (T2D) in Asian Indians using a data-driven optimization approach. Dietary, behavioral, and demographic assessments were performed on 18,090 adults participating in the nationally representative, population-based Indian Council of Medical Research-India Diabetes (ICMR-INDIAB) study. Fasting and 2-h postglucose challenge capillary blood glucose and glycosylated hemoglobin (HbA1c) were estimated. With HbA1c as the outcome, a linear regression model was first obtained for various glycemic categories: newly diagnosed diabetes (NDD), prediabetes (PD), and normal glucose tolerance (NGT). Macronutrient recommendations were formulated as a constrained quadratic programming problem (QPP) to compute optimal macronutrient compositions that would reduce the sum of the difference between the estimated HbA1c from the linear regression model and the targets for remission (6.4% for NDD and 5.6% for PD) and prevention of progression in T2D in PD and NGT groups. Four macronutrient recommendations (%E- Energy) emerged for 1) diabetes remission in NDD: carbohydrate, 49-54%; protein, 19-20%; and fat, 21-26%; 2) PD remission to NGT: carbohydrate, 50-56%; protein,18-20%; fat, 21-27%; 3 and 4) prevention of progression to T2D in PD and NGT: carbohydrate, 54-57% and 56-60%; protein, 16-20% and 14-17%, respectively; and fat 20-24% for PD and NGT. We recommend reduction in carbohydrates (%E) and an increase in protein (%E) for both T2D remission and for prevention of progression to T2D in PD and NGT groups. Our results underline the need for new dietary guidelines that recommend appropriate changes in macronutrient composition for reducing the burden due to diabetes in South Asia.

Altered macronutrient composition and genetics influence the complex transcriptional network associated with adiposity in the Collaborative Cross

BackgroundObesity is a serious disease with a complex etiology characterized by overaccumulation of adiposity resulting in detrimental health outcomes. Given the liver’s critical role in the biological processes that attenuate adiposity accumulation, elucidating the influence of genetics and dietary patterns on hepatic gene expression is fundamental for improving methods of obesity prevention and treatment. To determine how genetics and diet impact obesity development, mice from 22 strains of the genetically diverse recombinant inbred Collaborative Cross (CC) mouse panel were challenged to either a high-protein or high-fat high-sucrose diet, followed by extensive phenotyping and analysis of hepatic gene expression.ResultsOver 1000 genes differentially expressed by perturbed dietary macronutrient composition were enriched for biological processes related to metabolic pathways. Additionally, over 9000 genes were differentially expressed by strain and enriched for biological process involved in cell adhesion and signaling. Weighted gene co-expression network analysis identified multiple gene clusters (modules) associated with body fat % whose average expression levels were influenced by both dietary macronutrient composition and genetics. Each module was enriched for distinct types of biological functions.ConclusionsGenetic background affected hepatic gene expression in the CC overall, but diet macronutrient differences also altered expression of a specific subset of genes. Changes in macronutrient composition altered gene expression related to metabolic processes, while genetic background heavily influenced a broad range of cellular functions and processes irrespective of adiposity. Understanding the individual role of macronutrient composition, genetics, and their interaction is critical to developing therapeutic strategies and policy recommendations for precision nutrition.

Short communication: the effects of a semi-synthetic diet with inclusion of black soldier fly larvae meal on health parameters of healthy adult cats.

In recent years, black soldier fly larvae meal (Hermetia illucens; BSFLM) has gained attention as a high value alternative protein source that is of great interest to the pet food industry. However, little is known regarding the effects of BSFLM on health parameters in adult cats. Thus, the objective of the current study was to determine the short-term effects of a semi-synthetic diet containing 4.6% inclusion of BSFLM on complete blood count (CBC) and serum biochemistry profile of healthy adult cats. Healthy adult male cats (n = 8; 1.4 yr) were fed the experimental diet for 21 d (experimental period) to maintain BW. Cats were washed in on a commercial diet and blood samples were collected before the start and at the end of the experimental period to measure gross health parameters. Results were analyzed as one-way ANOVA using the GLIMMIX procedure in SAS with cat as a random effect (SAS v. 9.4, The SAS Institute, Cary, NC). Cats lost an average of 5% of their BW (P = 0.0003) due to a concurrent decrease in food intake. A significant increase of alanine aminotransferase, chloride, potassium, sodium, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration was observed on day 21 vs. baseline (P < 0.05). In contrast, albumin, amylase, calcium, cholesterol, eosinophil, lymphocyte, monocyte, mean platelet volume, red blood cells, total protein, total solid proteins, and urea decreased over time (P < 0.05). However, all CBC and serum biochemistry parameters stayed within reference range for adult cats, with exception of glucose and mean corpuscular hemoglobin concentration that were above and below the reference range, respectively. Transient increases in glucose concentrations were likely due to sedation with dexmedetomidine prior to blood collection. The changes observed over time in the aforementioned parameters are likely due to changes in macronutrient composition of the diets offered prior to and during the experimental period (commercial diet vs. semi-synthetic diet, respectively) and cannot be attributed solely to a unique property of BSFLM. In conclusion, cats fed a semi-synthetic diet containing 4% BSFLM inclusion for 21 d remained healthy with no clinically relevant changes in CBC and serum biochemistry parameters. Further research should focus on longer term feeding studies and the ability of BSFLM to support the health and well-being of cats.

Changes in macronutrients of human milk after bolus feeding: a simulation study.

Enteral nutrition supply to preterm infants requires feeding through a feeding tube. The aim of this study was to evaluate changes in macronutrient composition of human milk (HM) while passing through a gastric feeding tube. Simulated real-life practice tube feeding was performed by using an infusion pump connected to a feeding tube. A human milk analyzer was used to compare the pre infusion and post infusion macronutrient contents of HM. There was a significant decrease in fat (from 4.06 ± 0.6 g/100 ml to 3.95 ± 0.6 g/100 ml), carbohydrates (from 7.51 ± 0.4 g/100 ml to 7.33 ± 0.5 g/100 ml), and energy content (from 70.77 ± 5.4 kcal/100 ml to 69.72 ± 0.5 kcal/100 ml) after passing through the feeding tube (P < 0.001). A simulated real-life bolus tube feeding model demonstrated small but significant decreases in fat, carbohydrate, and energy content. The biological significance of our results to the very low birth weight infants should be further studied.

Marsupial and monotreme milk-a review of its nutrient and immune properties.

All mammals are characterized by the ability of females to produce milk. Marsupial (metatherian) and monotreme (prototherian) young are born in a highly altricial state and rely on their mother’s milk for the first part of their life. Here we review the role and importance of milk in marsupial and monotreme development. Milk is the primary source of sustenance for young marsupials and monotremes and its composition varies at different stages of development. We applied nutritional geometry techniques to a limited number of species with values available to analyze changes in macronutrient composition of milk at different stages. Macronutrient energy composition of marsupial milk varies between species and changes concentration during the course of lactation. As well as nourishment, marsupial and monotreme milk supplies growth and immune factors. Neonates are unable to mount a specific immune response shortly after birth and therefore rely on immunoglobulins, immunological cells and other immunologically important molecules transferred through milk. Milk is also essential to the development of the maternal-young bond and is achieved through feedback systems and odor preferences in eutherian mammals. However, we have much to learn about the role of milk in marsupial and monotreme mother-young bonding. Further research is warranted in gaining a better understanding of the role of milk as a source of nutrition, developmental factors and immunity, in a broader range of marsupial species, and monotremes.

Impaired Metabolic Flexibility to High-Fat Overfeeding Predicts Future Weight Gain in Healthy Adults.

The ability to switch fuels for oxidation in response to changes in macronutrient composition of diet (metabolic flexibility) may be informative of individuals’ susceptibility to weight gain. Seventy-nine healthy, weight-stable participants underwent 24-h assessments of energy expenditure and respiratory quotient (RQ) in a whole-room calorimeter during energy balance (EBL) (50% carbohydrate, 30% fat) and then during 24-h fasting and three 200% overfeeding diets in a crossover design. Metabolic flexibility was defined as the change in 24-h RQ from EBL during fasting and standard overfeeding (STOF) (50% carbohydrate, 30% fat), high-fat overfeeding (HFOF) (60% fat, 20% carbohydrate), and high-carbohydrate overfeeding (HCOF) (75% carbohydrate, 5% fat) diets. Free-living weight change was assessed after 6 and 12 months. Compared with EBL, RQ decreased on average by 9% during fasting and by 4% during HFOF but increased by 4% during STOF and by 8% during HCOF. A smaller decrease in RQ, reflecting a smaller increase in lipid oxidation rate, during HFOF but not during the other diets predicted greater weight gain at both 6 and 12 months. An impaired metabolic flexibility to acute HFOF can identify individuals prone to weight gain, indicating that an individual’s capacity to oxidize dietary fat is a metabolic determinant of weight change.

Impaired Metabolic Flexibility to High-Fat Overfeeding Predicts Future Weight Gain

The ability to switch fuels for oxidation in response to changes in macronutrient composition of diet (metabolic flexibility) may be informative of the individual susceptibility to weight gain. Seventy-nine healthy, weight-stable subjects underwent 24-h assessments of energy expenditure and respiratory quotient (RQ) in a whole-room calorimeter during energy balance (EBL; 50% carbohydrate, 30% fat) and then during 24-h fasting and three 200% overfeeding diets in a crossover design. Metabolic flexibility was defined as the change in 24-h RQ from EBL during fasting and standard (SOF: 50% carbohydrate, 30% fat), high-fat (FNP: 60% fat, 20% carbohydrate), and high-carbohydrate (CNP: 75% carbohydrate, 5% fat) overfeeding diets. Free-living weight change was assessed after 6 and 12 months. Compared to EBL, RQ decreased on average by 9% during fasting and by 4% during FNP, while increasing by 4% during SOF and by 8% during CNP. Smaller decrease in RQ, reflecting smaller increase in lipid oxidation rate, during FNP but not during other diets, predicted greater weight gain at both 6 and 12 months. An impaired metabolic flexibility to acute, high-fat overfeeding identify individuals prone to gain weight, indicating that the individual capacity to oxidize dietary fat is a metabolic predictor of weight change.

Evaluation of Variability in Resting Energy Expenditure and Its Relationship with Macronutrients and Gestational Weight Gain During the Second Trimester of Pregnancy (P11-136-19)

Abstract Objectives Resting energy expenditure (REE) comprises 60% of total energy expenditure and variations may be associated with gestational weight gain (GWG). There is a paucity of research investigating the relationship between REE and GWG. We investigated variations in REE and dietary composition throughout the second trimester and their association with GWG. Methods In this controlled trial, pregnant women (N = 16, mean age of 29.9 ± 4.3 years) with a gestational age &lt; 17 weeks used the Breezing™ device for 13 weeks. This device is a real-time metabolism tracker that measures REE via indirect calorimetry. Height, weight, REE, and dietary intake via 24-hr recall were assessed every 2 weeks. Rate of GWG was calculated as weight gain divided by number of study weeks. Early (EC, GA wks 14–21), late (LC, GA wks 21–28), and overall (OC, GA wks 14–28) changes in macronutrient composition, REE, and GWG were used to evaluate time-specific associations. Group differences were analyzed using a General Linear Model in SPSS Version 25. Results Among the 16 participants, 25% of women were normal weight, 50% were overweight, and 25% were obese at study start. Women had a total and rate of GWG of 8.1 ± 2.9 kg and 0.6 ± 0.2 kg/wk, respectively. REE increased 72 ± 211 kcals/d during the early period, 121 ± 294 kcals/d during the late period, and 200 ± 316 kcals/d overall (from 1544 ± 237 kcal/d to 1744 ± 384 kcal/d). Early changes in REE were significantly correlated with the late changes in total (r = 0.52, P = 0.04) and rate of weight gain (r = 0.54, P = 0.03). A correlation between overall changes in REE and total weight gain was moderate and approached significance, r = 0.44, P = 0.09. Changes in total energy, fat, carbohydrate, and protein intake were not correlated with changes in REE; however, a moderate relationship between early changes in REE and overall changes in energy intake approached significance, r = 0.46, P = 0.07. Changes in GWG and REE did not differ among normal, overweight, or obese women (EC: F(2,15) = 0.36, P = 0.70; LC: F(2,15) = 2.37, P = 0.13; OC: F(2.15) = 1.27, P = 0.31). Conclusions Early changes in REE demonstrated a moderate, positive correlation with total and rate of GWG suggesting that assessment of REE early in pregnancy may help understand changes in GWG. Future research that evaluates both REE and dietary composition throughout pregnancy may provide insight into appropriate GWG. Funding Sources Project HoneyBee, Arizona State University.

Effects of 6‐weeks of Time‐Restricted Feeding in Normal Weight Middle‐Aged and Older Adults

Calorie restriction (CR) improves multiple indicators of healthspan and physiological function in humans. However, CR is contraindicated in normal‐weight middle‐aged and older (MA/O) adults because it induces deleterious adaptations, such as reductions in body mass (including skeletal muscle mass) and bone mineral density (BMD). Time‐restricted feeding (TRF), which involves consuming all calories within an 8–10‐hour window and fasting for the remainder of the day, has the potential to maximize the benefits of CR while minimizing these possible adverse effects in normal‐weight MA/O adults. We performed a randomized controlled crossover clinical trial to evaluate the feasibility, tolerability and lack of adverse changes in body composition and BMD following six weeks of TRF vs. normal feeding (NF) in normal‐weight MA/O adult men and women (n=22, 67±6 years). A secondary aim was to explore the potential efficacy of TRF for improving select indices of healthspan and physiological function. Adherence to TRF was excellent with all subjects successfully reducing their eating window from 11.7 ± 0.3 hours/day to within 8 hours/day (7.6±0.1 hours/day, p&lt;0.05). Compared with NF, all subjects maintained their regular daily energy intake during TRF, with no significant changes in macronutrient composition or overall diet quality, as assessed using the Healthy Eating Index (HEI; NF= 63±3 vs. TRF= 61±2, p&gt;0.05). TRF was well‐tolerated with no increases in self‐reported desire to eat, satiety, or stomach fullness (all p&gt;0.05 vs. NF) and interestingly, lower feelings of hunger (p&lt;0.01 vs. NF). Importantly, TRF did not affect body mass, BMD or body composition (all p&gt;0.05 vs. NF). TRF improved two indices of cardiorespiratory fitness, including a reduced heart rate during submaximal exercise (p&lt;0.05) and increased distance traveled during a 6‐minute walk test (NF=570±12 m vs. TRF=585±11 m, p&lt;0.05). Glucose tolerance, assessed during a 2‐hour oral glucose tolerance test in a subset of subjects (n=16), also improved with TRF (NF=15,500±300 mg/dL x min vs. TRF=14,500±200 mg/dL x min, p&lt;0.05). These findings suggest that TRF is feasible and well‐tolerated in normal‐weight MA/O adults and is not associated with adverse changes in body composition or BMD. Moreover, TRF may improve cardiorespiratory fitness and glycemic control, two important indicators of healthspan and future risk of chronic disease, disability, and/or frailty. Thus, TRF may be a practical alternative to conventional CR for improving healthspan in normal‐weight MA/O adults.Support or Funding InformationSupported by Aging T32 AG000279This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of macronutrient manipulation on postprandial metabolic responses in overweight males with high fasting lipids during simulated shift work: A randomized crossover trial

Meals consumed out of synchronisation with normal circadian rhythms are associated with metabolic dysregulation. Changes in macronutrient composition of meals can improve metabolic responses during the day. Therefore, we aimed to investigate whether macronutrient manipulation of meals alters postprandial glucose and lipid responses and the expression of circadian genes during the night. In a randomised crossover trial, 16 overweight males with high fasting lipids were fed isocaloric meals (2.7MJ) at 0000h. The meals differed primarily in total fat and total sugars content (control (8% total sugar, 5% saturated fat) vs test (16% total sugar, 26% saturated fat)). Postprandial blood samples were collected for glucose, insulin (3h) and triglycerides (6h) and analysed as incremental area under the curve (iAUC). RNA was extracted at 0h, 2h and 4h and changes in expressions of the circadian genes clock and Per 1-3 analysed. Postprandial glucose (p=0.04) and insulin iAUC (p=0.02) were significantly higher after consumption of the test meal compared to the control meal. Postprandial triglyceride iAUC was not statistically different between the two meal types (p=0.72). No change in circadian gene expression was observed after the two meals. Our results showed that macronutrient composition affects postprandial metabolic response at night. It emphasizes the need to consider the role and effects of night time eating, when developing metabolic disease prevention strategies for shift workers. ACTRN12618001115224. WEBSITE OF TRIAL REGISTRY: http://www.anzctr.org.au/. Retrospectively registered after data collection.

Macronutrient Composition of the Australian Population's Diet; Trends from Three National Nutrition Surveys 1983, 1995 and 2012.

Although the role of individual macronutrients in the development of obesity remains controversial, changes in macronutrient composition of the diet may have played a causal role in the obesity epidemic. The aim of this analysis was to determine the percentage energy (%E) for protein, carbohydrate and fat of Australian adults’ diets over time. Cross-sectional, national nutrition surveys from 1983, 1995 and 2012 assessed diet using one 24 h recall. The prevalence of obesity increased between each survey, from 9.6% to 19.7% and 27.7%. Protein (%E) differed between each survey and contributed 17.7%, 16.8% and 18.3% energy in 1983, 1995 and 2012, respectively (p < 0.001). Carbohydrate (%E) increased from 40.0% in 1983 to 44.9% in 1995 (p < 0.001), with no change in dietary fibre but declined in 2012 to 43.1%. Fat (%E) declined between each survey from 35.3%, 31.9%, to 30.9%, respectively (p < 0.001). Alcohol (%E) has declined for younger adults and men but intake increased for women aged >45 years. Prospective cohort studies with comprehensive assessment of foods consumed, together with measurements of weight and height, will advance the understanding of the relationship between macronutrients and changes in body weight and obesity.

Complex interactions of circadian rhythms, eating behaviors, and the gastrointestinal microbiota and their potential impact on health.

Human health is intricately intertwined with the composition and function of the trillions of microorganisms that make up the gastrointestinal (GI) microbiome. The GI microbiome is essentially a microbial organ that provides metabolic, immunologic, and protective functions for the host. Habitual diet, changes in macronutrient composition, and consumption of nondigestible dietary fibers have all been shown to impact the human GI microbiome. Intriguingly, the impact of diet on the microbiome may be related not only to what humans eat but also to the timing of food consumption. Emerging preclinical research suggests that gut microbes experience diurnal rhythms, and the health effects of eating patterns, including time-restricted feeding and meal frequency, may be related to the GI microbiome. Herein, the complex connections among circadian rhythms, eating behaviors, the GI microbiome, and health are reviewed, highlighting the need for additional translational research in this area.

Changes in total energy intake and macronutrient composition after bariatric surgery predict long-term weight outcome: findings from the Swedish Obese Subjects (SOS) study

Background: Approximately 20-30% of obese patients do not achieve successful weight outcomes after bariatric surgery.Objective: We examined whether short-term changes (≤0.5 y postsurgery) in energy intake and macronutrient composition after bariatric surgery could predict 10-y weight change.Design: Participants were recruited from the Swedish Obese Subjects (SOS) study, which was a matched (nonrandomized) prospective trial that compared bariatric surgery with usual care for obese patients. A total of 2010 patients who underwent bariatric surgery were included in the study. Physical examinations (e.g., weight) and questionnaires (e.g., dietary questionnaire) were completed before and 0.5, 1, 2, 3, 4, 6, 8, and 10 y after surgery. For the main analytic strategy, a linear mixed model was implemented, which included repeated measures with a random intercept and an unstructured covariance matrix.Results: Short-term changes in energy intake (P < 0.001) and in relative proportions of energy from carbohydrates (P < 0.001), fat (P < 0.001), and protein (P < 0.05) were associated with 10-y weight change after bariatric surgery. At the 10-y follow-up, men and women with the largest reductions in energy intake had lost 7.3% and 3.9% more weight, respectively, compared with that of subjects with the smallest intake reductions (P < 0.001). Greater weight loss was achieved in men and women who favored protein and carbohydrates over fat and in subjects who favored protein over carbohydrates than in individuals who favored the opposite changes in macronutrient composition (P < 0.05).Conclusions: The level of energy restriction that is achieved at 0.5 y after bariatric surgery predicts long-term weight loss. Weight loss is also associated with a changing dietary macronutrient composition. This trial was registered at clinicaltrials.gov as NCT01479452.

Macronutrient Composition of Menu Offerings in Fast Food Restaurants in the U.S.

A high intake of fast food is associated with increased obesity risk. This study assessed recent changes in caloric content and macronutrient composition in large U.S. fast food restaurants. Data from the MenuStat project included 11,737 menu items in 37 fast food restaurants from 2012 to 2014. Generalized linear models were used to examine changes in the caloric content and corresponding changes in the macronutrient composition (non-sugar carbohydrates, sugar, unsaturated fat, saturated fat, and protein) of menu items over time. Additionally, macronutrient composition was compared in menu items newly introduced in 2013 and 2014, relative to 2012. Analyses, conducted in January 2016, controlled for restaurant and were stratified by menu categories. Overall, there was a 22-calorie reduction in food items from 2012 to 2014. Beverages had a 46-calorie increase, explained by an increase in calories from sugar (12 calories) and saturated fat (16 calories). Newly introduced main courses in 2014 had 59 calories fewer than those on 2012 menus, explained by a 54-calorie reduction in unsaturated fat, while other macronutrient content remained fairly constant. Newly introduced dessert items in 2014 had 90 calories more than those on 2012 menus, explained primarily by an increase of 57 calories of sugar. Overall, there were relatively minor changes in menu items' caloric and macronutrient composition. Although declines in caloric content among newly introduced fast food main courses may improve the public's caloric intake, it appears that the macronutrient composition of newly introduced items did not shift to a healthier profile.

Simulating the Influence of Changes in Macronutrient Composition and Amounts in the American Diet From 1971–2008 on Body Composition Changes and Their Contribution to the Obesity Epidemic

BackgroundThe obesity epidemic in the US has many suggested causes. We investigated the role that changes in diet macronutrient composition (carbohydrate, protein and fat) and amounts had in contributing to the observed changes in body weight and composition between 1971 and 2008.MethodsUsing a previously validated physiologically‐based mathematical model that simulates the effect of dietary macronutrient composition and amounts on body weight and composition changes in sedentary men and women, we simulated body weight changes from 1971 through 2008 based on dietary macronutrient composition and amounts reported from NHANES and the Centers for Disease Control and Prevention (CDC).ResultsSimulated body weight change patterns for both men and women were similar to those actually observed, though body weight values for men were generally over‐predicted and for women were under‐predicted. Final simulated body weights for men and women were +9.3% and −10.4% actual reported values, respectively.ConclusionsWe conclude that the obesity epidemic has been predominantly driven by the amounts and types of consumed macronutrients in food, and that if the American diet were to return to pre‐epidemic macronutrient levels and composition the obesity epidemic would likely reverse and disappear.

Day to day variability in fat oxidation and the effect after only 1 day of change in diet composition.

Indirect calorimetry is a common and noninvasive method to estimate rate of fat oxidation (FatOx) during exercise, and test-retest reliability should be considered when interpreting results. Diet also has an impact on FatOx. The aim of the present study was to investigate day to day variations in FatOx during moderate exercise given the same diet and 2 different isoenergetic diets. Nine healthy, moderately-trained females participated in the study. They performed 1 maximal oxygen uptake test and 4 FatOx tests. Habitual diets were recorded and repeated to assess day to day variability in FatOx. FatOx was also measured after 1 day of fat-rich (26.8% carbohydrates (CHO), 23.2% protein, 47.1% fat) and 1 day of CHO-rich diet (62.6% CHO, 20.1% protein, 12.4% fat). The reliability test revealed no differences in FatOx, respiratory exchange ratio (RER), oxygen uptake, carbon dioxide production, heart rate, blood lactate concentration, or blood glucose between the 2 habitual diet days. FatOx decreased after the CHO-rich diet compared with the habitual day 2 (from 0.42 ± 0.15 to 0.29 ± 0.13 g·min(-1), p < 0.05). No difference was found in FatOx between fat-rich diet and the 2 habitual diet days. FatOx was 31% lower (from 0.42 ± 0.14 to 0.29 ± 0.13 g·min(-1), p < 0.01) after the CHO-rich diet compared with the fat-rich diet. Using RER data to measure FatOx is a reliable method as long as the diet is strictly controlled. However, even a 1-day change in macronutrient composition will likely affect the FatOx results.

A brief review of higher dietary protein diets in weight loss: a focus on athletes.

Thermodynamics dictates that for body weight (i.e. stored substrate) loss to occur a person must ingest less energy than they expend. Athletes, who owing to their oftentimes large daily energy expenditures, may have greater flexibility than non-athletes in this regard; however, they may also have different goals for weight loss. In particular, weight lost may be less important to an athlete than from which compartment the weight is lost: fat or lean. A critical question is thus, what balance of macronutrients might promote a greater fat loss, a relative retention of lean mass, and still allow athletic performance to remain uncompromised? It is the central thesis of this review that dietary protein should be a nutrient around which changes in macronutrient composition should be framed. The requirement for protein to sustain lean mass increases while in negative energy balance and protein, as macronutrient, may have advantages with respect to satiety during energy balance, and it may allow greater fat loss during a negative energy balance. However, athletes should be mindful of the fact that increasing dietary protein intake while in negative energy balance would come at the ‘expense’ of another macronutrient. Most recently there has been interest in lower carbohydrate diets, which may not allow performance to be sustained given the importance of dietary carbohydrate in high-intensity exercise. The relative merits of higher protein diets for athletes are discussed.

The source of dietary non-protein energy affectsin vivoprotein digestion in African catfish (Clarias gariepinus)

The development of chyme characteristics and the in vivo digestion of crude protein (CP) were assessed in response to different dietary sources of non-protein energy. African catfish (Clarias gariepinus) were fed a starch or fat diet for 28 days, and faecal CP apparent digestibility coefficient (ADC) was determined by a marker method. After the consumption of a single meal, chyme was collected from four compartments of the gastrointestinal tract and viscosity, dry matter (DM), CP and marker concentration were measured. Replacing dietary fat by starch resulted in a lower faecal CP ADC (P < 0.05), even though CP originated from the same dietary ingredients. A higher inclusion level of starch led to a higher viscosity of chyme in the stomach, but a lower DM content, compared to the fat diet (P < 0.05). Gastric evacuation was delayed in starch fed fish, likely due to the high viscosity of chyme. After evacuation of chyme into the proximal intestine, no significant differences in chyme characteristics were observed between diets (P > 0.05). Changes in macronutrient composition can alter the environment in which CP digestion takes place. We suggest that for the formulation of highly digestible diets, the entire feed matrix needs to be considered, rather than single ingredients.

Maternal nutrition affects offspring performance via maternal care in a subsocial spider

Provisioning of nutrients to the young during parental care is one of the mechanisms by which parents can affect growth and survival of their young and thus their reproductive success. We examined the hypothesis that food quality, i.e., ratio of macronutrients, provided to the young via maternal care affects their performance and the female’s reproductive success. The subsocial spider Stegodyphus lineatus exhibits intensive maternal care behaviors, including feeding the young and matriphagy (consumption of the mother). Our results showed that a protein-enriched diet resulted in larger females at maturation and higher survival of young, relative to intermediate or lipid-enriched diets. However, fecundity was not affected by female diet. We suggest that most of the nutrients are provided to the young during maternal care rather than deposited in the eggs, allowing females to economize on limited nutritional reserves. Females before maternal care showed a low protein and high lipid content relative to females before maturation and oviposition, suggesting a change in the nutritional requirement of females before maternal care. This change in macronutrient composition may be adaptive for the success of the young in the wild and shows a novel approach to animals’ ability to increase their reproductive success. Field-collected females showed a similar macronutrient composition as that of protein-enriched females in the lab, suggesting a high reproductive success of females in the wild. To our knowledge, this is the first time the importance of different macronutrients to females’ reproductive success is examined during reproduction.