The Effects of Dietary Protein at Breakfast and Across the Day on Appetite Control & Satiety, Food Intake, and Sleep Quality

The movement to adopt healthful lifestyle practices to reduce the prevalence of obesity and associated chronic diseases has garnered global interest [1]. As such, the desire to consume more protein-rich foods is a commonly used strategy due to the documented improvements in weight management observed with higher-protein (HP) diets, ranging from 1.2-1.6 g protein•kg body weight-1•d-1[2-6]. One postulated mechanism through which HP diets elicit greater weight (and fat) losses includes the improvements in ingestive behavior which appear to be mediated by a number of satiety-stimulating, physiological and/or hedonic pathways, and lead to reductions in daily food intake [3]. The main objectives of this dissertation were to: 1) Test whether the consumption of higher-protein (HP) compared with normal-protein (NP) meals consumed at each eating occasion reduces free-living, daily carbohydrate and fat intakes in overweight women during energy balance conditions and whether the distribution of protein consumed throughout the day affects food intake outcomes. 2) Test whether the consumption of a HP energy-restriction diet reduces carbohydrate and fat intakes through improvements in daily appetite, satiety, and food cravings compared with NP versions and to test whether protein type within the NP diets alters protein-related satiety. 3) Test whether the consumption of breakfast vs. breakfast skipping improves subjective and hormonal markers of appetite, satiety, and sleep in combination with ad libitum food intake in young adults prone to subclinical sleep disturbances. This dissertation is organized into chapters which consist of published manuscripts or manuscripts formatted for submission to peer-reviewed journals. Details pertaining to the status of each manuscript are included at the beginning of each chapter. Chapter 2 includes a comprehensive review of the intervention-based evidence surrounding the consumption of breakfast vs. breakfast skipping with specific emphasis on appetite control and satiety, energy expenditure, and sleep and circadian health. Chapter 3 includes a randomized cross-over trial which examines the effects of increased dietary protein intake across the day on free-living ad libitum food intake in overweight women during weight maintenance conditions. As a secondary outcome, the effects of protein distribution across the day were tested. Chapter 4 includes a randomized cross-over trial which examines the effects of consuming a HP energy-restriction diet vs. NP energy-restriction diet on appetite control, food cravings, and free-living ad libitum food intake in overweight women. Secondary assessments examining whether protein type within the NP diets alters protein-related satiety were also included. Chapter 5 includes a randomized cross-over trial examines whether breakfast consumption compared to breakfast skipping improves subjective and hormonal markers of appetite, satiety, and sleep in young adults. Finally, Chapter 6 summarizes the main dissertation findings and presents future directions for research. Collectively, the findings from this dissertation demonstrated the following: 1) Providing 30 g protein/meal at each eating occasion throughout the day did not influence free-living, daily intake of highly palatable, carbohydrate and fat-rich foods in overweight women; 2) While appetite control, satiety, and food cravings were improved following a higher-protein, energy-restriction diet, increased protein consumption did not reduce free-living carbohydrate and fat intake throughout the free-living test day in overweight, healthy women exposed to highly palatable foods; and 3) the daily consumption of breakfast improved appetite control and diet quality, through reductions in unhealthy evening snacking, and may support improvements in some aspects of sleep health in healthy young professionals. These findings provide evidence which suggests that the inclusion of increased dietary protein at breakfast and across the day are dietary strategies for improving some aspects of appetite control. Notably, not all findings demonstrated consistent support of appetite control. Thus, this work highlights that the effectiveness of including dietary protein to support appetite control and improved eating behavior as contributing factors underlying weight management is contingent upon various physiological and behavioral circumstances. The movement to adopt healthful lifestyle practices to reduce the prevalence of obesity and associated chronic diseases has garnered global interest [1]. As such, the desire to consume more protein-rich foods is a commonly used strategydue to the documented improvements in weight management observed with higher-protein (HP) diets, rangingfrom 1.2-1.6 gprotein•kg body weight-1•d-1[2-6]. One postulated mechanism through which HP diets elicit greater weight (and fat) losses includes the improvements in ingestive behavior which appear to be mediated by a number of satiety-stimulating, physiological and/or hedonic pathways, and lead to reductions in dailyfood intake [3].The main objectives of this dissertation were to: 1) Test whether the consumption of higher-protein (HP) compared with normal-protein (NP) meals consumed at each eating occasion reduces free-living, daily carbohydrate and fat intakes in overweight women during energy balance conditions and whether the distribution of protein consumed throughout the day affects food intake outcomes. 2) Test whether the consumption of a HP energy-restriction diet reduces carbohydrate and fat intakes through improvements in daily appetite, satiety, and food cravings compared with NP versions and to test whether protein type within the NP diets alters protein-related satiety. 3) Test whether the consumption ofbreakfast vs. breakfast skippingimproves subjective and hormonal markers of appetite, satiety, and sleep in combination with ad libitum food intake in young adults prone to subclinical sleep disturbances.This dissertation is organized into chapters which consist of published manuscripts or manuscripts formattedfor submission to peer-reviewedjournals. Details pertainingto the status of each manuscript are included atthe beginning of each chapter. Chapter 2includes a comprehensive review of the intervention-based evidence surroundingthe consumption of breakfast vs. breakfast skipping with specific emphasis on appetite control and satiety, energ

Higher Protein Density Diets Are Associated With Greater Diet Quality and Micronutrient Intake in Healthy Young Adults

Objective: This study characterized habitual dietary protein intake in healthy young adults entering military service and explored whether diet protein density is associated with diet quality and micronutrient intake.Methods: An FFQ was used to estimate habitual dietary intake and calculate HEI scores in 276 males [mean(SD), age:21.1y(3.8)] and 254 females [age:21.2y(3.7)]. Multivariate-adjusted MANCOVA and ANCOVA models were used to identify associations between protein density quartiles and HEI scores and micronutrient intake. Higher HEI components scores for sodium, refined grains, and empty calories indicate lower intake; higher scores for all other components indicate higher intakes.Results: Mean(SD) energy-adjusted protein intakes were 29.3(3.2), 36.0(1.4), 40.8(1.3), and 47.9(3.9) g/1,000 kcal for protein density quartiles 1–4, respectively. For males, empty calorie scores as well as dark green and orange vegetable scores were higher in quartiles 3 and 4 than 1 and 2 (all, p < 0.05). Scores for total vegetable, dairy, and total protein foods were lower in quartile 1 vs. quartiles 2, 3, and 4 (all, p < 0.05). Sodium scores decreased as quartiles increased (p < 0.001). Total HEI, fruit, whole grains, seafood and plant protein, fatty acids, and refined grain scores did not differ. For females, total HEI, vegetable, and total protein foods scores were higher in quartiles 3 and 4 than 1 and 2 (all, p < 0.05). Empty calorie scores increased as quartile increased (p < 0.05). Dairy scores were higher in quartiles 2, 3, and 4 than 1 (p < 0.05). Whole fruit scores were lowest in quartile 1 (p < 0.05). Whole grain as well as seafood and plant protein scores were higher in quartile 4 vs. 1 (both, p < 0.05). Sodium scores decreased as quartile increased (p < 0.001). Fatty acids scores did not differ. For males and females, micronutrient intakes progressively increased across quartiles with the exception of calcium and vitamin C, (all, p < 0.05). Intakes remained nearly the same when controlled for fruit and vegetable intake.Conclusion: These cross-sectional data suggest that habitually consuming a higher protein density diet is associated with better scores for some, but not all, diet quality components in males, better overall diet quality scores in females, and greater intakes of micronutrients in both male and female healthy, young adults entering military service

Growing up strong: The importance of physical, mental, and emotional strength during childhood and adolescence with focus on dietary factors

Childhood and adolescence are critical time periods for growth and development. Given the current physical and psychological health concerns affecting United States youth, an emerging area of interest exists supporting the importance of physical and psychological aspects of strength for health, resilience, and well-being through these life stages. This synopsis highlights the key concepts that were presented within the 2018 Strength Summit conference, entitled The Role of Strength in Optimal Health and Well-being. During the conference, strength was broadly defined as the ability to successfully respond to a challenge. Although much of the current research focuses on strength from a muscle function and performance perspective, mental and emotional strength are also important components of overall health and well-being, especially in children and adolescents. This paper provides a brief overview of the clinical and/or research-based strength outcomes, summarizes the relationship between strength and health, and discusses evidence-based dietary factors that promote strength in children and adolescents. Novelty Building physical, mental, and emotional strength during childhood and adolescence lays the foundation for health and well-being. Emerging evidence indicate positive associations between diet quality and strength in children and adolescents. Promising areas include the promotion of family-based meals, with focus on breakfast, for improved strength in United States youth.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Physiological limitations of protein foods ounce equivalents and the underappreciated role of essential amino acid density in healthy dietary patterns

Protein quality is an important component of protein intake to support growth, development, and maintenance of essential body tissues and functions. Therefore, protein quality should be emphasized as a key characteristic during protein food selection within the larger context of healthy dietary patterns, especially when considering the wide variance of protein quality across animal- and plant-based foods. However, the USDA Dietary Guidelines for Americans (DGA) do not address specific protein quality recommendations within their protein foods ounce equivalents guidance or as a component of Healthy U.S. Style, Healthy Vegetarian, and Healthy Mediterranean Style dietary patterns. In addition, the protein foods ounce equivalents within the DGA are not established on any obvious metabolic equivalency characteristic [i.e., energy, protein, or essential amino acid (EAA) content], which creates misleading messaging of equivalent functional and metabolic benefit across protein foods. EAA content is a key characteristic of protein quality and can be a practical focal point for protein intake recommendations and achieving healthy dietary patterns. This review discusses the importance of protein quality, the state of messaging within DGA recommendations, and proposes EAA density (i.e., EAA content relative to total energy) as one practical approach to improve current dietary recommendations. Two recent publications that evaluated the DGA protein foods ounce equivalents based on metabolic effect and their application within DGA recommended dietary patterns are discussed. J Nutr 2021;151:3276 3283

Examination of Protein Quantity and Protein Distribution across the Day on Ad Libitum Carbohydrate and Fat Intake in Overweight Women

BACKGROUND: The effects of meal-specific protein quantity and protein distribution throughout the day on daily food intake are relatively unknown. OBJECTIVES: The aims were to test 1) whether the consumption of higher-protein (HP) compared with normal-protein (NP) meals consumed at each eating occasion reduce free-living, daily carbohydrate and fat intakes in overweight women during energy balance conditions and 2) whether the distribution of protein consumed throughout the day affects food intake outcomes. METHODS: Seventeen women [mean ± SEM age: 33 ± 1 y; body mass index (in kg/m2): 27.8 ± 0.1] completed the following tightly controlled, crossover design study. Participants were provided with and randomly consumed three 6-d eucaloric diets containing NP or HP (15% or 25% of energy as protein, respectively). The protein content within the NP diet used an even distribution pattern (EVEN; 21 ± 1 g protein/meal) throughout the day, whereas the protein contents within the HP diets used either EVEN (35 ± 1 g protein/meal) or an uneven distribution pattern (UNEVEN; 19 ± 1 g protein/breakfast, 26 ± 1 g protein/lunch, 63 g protein/dinner). On day 7 of each diet, the participants were asked to consume the diet-specific absolute protein quantity (in grams) at each eating occasion but were provided with a surplus of carbohydrate- and fat-rich foods to consume, ad libitum, during each eating occasion. RESULTS: Eating more protein (HP compared with NP) or evenly distributing protein throughout the day (HP-EVEN compared with HP-UNEVEN) did not reduce the consumption of ad libitum fat- and carbohydrate-rich foods throughout the day (NP-EVEN: 2850 ± 240 kcal/d; HP-EVEN: 2910 ± 240 kcal/d; HP-UNEVEN: 3160 ± 200 kcal/d). Despite the lack of differences in daily energy intake, the breakfast meal within the HP-EVEN diet led to lower ad libitum carbohydrate and fat intakes than the breakfast meals in the NP-EVEN and HP-UNEVEN diet conditions (P < 0.05). CONCLUSION: Providing 30 g protein/meal at each eating occasion throughout the day did not influence free-living, daily intake of highly palatable, carbohydrate- and fat-rich foods in overweight women. This trial was registered at clinicaltrials.gov as NCT02614729

Examination of Protein Quantity and Protein Distribution across the Day on Ad Libitum Carbohydrate and Fat Intake in Overweight Women

BACKGROUND: The effects of meal-specific protein quantity and protein distribution throughout the day on daily food intake are relatively unknown. OBJECTIVES: The aims were to test 1) whether the consumption of higher-protein (HP) compared with normal-protein (NP) meals consumed at each eating occasion reduce free-living, daily carbohydrate and fat intakes in overweight women during energy balance conditions and 2) whether the distribution of protein consumed throughout the day affects food intake outcomes. METHODS: Seventeen women [mean ± SEM age: 33 ± 1 y; body mass index (in kg/m2): 27.8 ± 0.1] completed the following tightly controlled, crossover design study. Participants were provided with and randomly consumed three 6-d eucaloric diets containing NP or HP (15% or 25% of energy as protein, respectively). The protein content within the NP diet used an even distribution pattern (EVEN; 21 ± 1 g protein/meal) throughout the day, whereas the protein contents within the HP diets used either EVEN (35 ± 1 g protein/meal) or an uneven distribution pattern (UNEVEN; 19 ± 1 g protein/breakfast, 26 ± 1 g protein/lunch, 63 g protein/dinner). On day 7 of each diet, the participants were asked to consume the diet-specific absolute protein quantity (in grams) at each eating occasion but were provided with a surplus of carbohydrate- and fat-rich foods to consume, ad libitum, during each eating occasion. RESULTS: Eating more protein (HP compared with NP) or evenly distributing protein throughout the day (HP-EVEN compared with HP-UNEVEN) did not reduce the consumption of ad libitum fat- and carbohydrate-rich foods throughout the day (NP-EVEN: 2850 ± 240 kcal/d; HP-EVEN: 2910 ± 240 kcal/d; HP-UNEVEN: 3160 ± 200 kcal/d). Despite the lack of differences in daily energy intake, the breakfast meal within the HP-EVEN diet led to lower ad libitum carbohydrate and fat intakes than the breakfast meals in the NP-EVEN and HP-UNEVEN diet conditions (P < 0.05). CONCLUSION: Providing 30 g protein/meal at each eating occasion throughout the day did not influence free-living, daily intake of highly palatable, carbohydrate- and fat-rich foods in overweight women. This trial was registered at clinicaltrials.gov as NCT02614729

Mitigation of Muscle Loss in Stressed Physiology: Military Relevance

Military personnel may be exposed to circumstances (e.g., large energy deficits, sleep deprivation, cognitive demands, and environmental extremes) of external stressors during training and combat operations (i.e., operational stressors) that combine to degrade muscle protein. The loss of muscle protein is further exacerbated by frequent periods of severe energy deficit. Exposure to these factors results in a hypogonadal state that may contribute to observed decrements in muscle mass. In this review, lessons learned from studying severe clinical stressed states and the interventions designed to mitigate the loss of muscle protein are discussed in the context of military operational stress. For example, restoration of the anabolic hormonal status (e.g., testosterone, insulin, and growth hormone) in stressed physiological states may be necessary to restore the anabolic influence derived from dietary protein on muscle. Based on our clinical experiences, restoration of the normal testosterone status during sustained periods of operational stress may be advantageous. We demonstrated that in severe burn patients, pharmacologic normalization of the anabolic hormonal status restores the anabolic stimulatory effect of nutrition on muscle by improving the protein synthetic efficiency and limiting amino acid loss from skeletal muscle. Furthermore, an optimal protein intake, and in particular essential amino acid delivery, may be an integral ingredient in a restored anabolic response during the stress state. Interventions which improve the muscle net protein balance may positively impact soldier performance in trying conditions

Muscle Protein Synthesis and Whole-Body Protein Turnover Responses to Ingesting Essential Amino Acids, Intact Protein, and Protein-Containing Mixed Meals with Considerations for Energy Deficit

Protein intake recommendations to optimally stimulate muscle protein synthesis (MPS) are derived from dose-response studies examining the stimulatory effects of isolated intact proteins (e.g., whey, egg) on MPS in healthy individuals during energy balance. Those recommendations may not be adequate during periods of physiological stress, specifically the catabolic stress induced by energy deficit. Providing supplemental intact protein (20–25 g whey protein, 0.25–0.3 g protein/kg per meal) during strenuous military operations that elicit severe energy deficit does not stimulate MPS-associated anabolic signaling or attenuate lean mass loss. This occurs likely because a greater proportion of the dietary amino acids consumed are targeted for energy-yielding pathways, whole-body protein synthesis, and other whole-body essential amino acid (EAA)-requiring processes than the proportion targeted for MPS. Protein feeding formats that provide sufficient energy to offset whole-body energy and protein-requiring demands during energy deficit and leverage EAA content, digestion, and absorption kinetics may optimize MPS under these conditions. Understanding the effects of protein feeding format-driven alterations in EAA availability and subsequent changes in MPS and whole-body protein turnover is required to design feeding strategies that mitigate the catabolic effects of energy deficit. In this manuscript, we review the effects, advantages, disadvantages, and knowledge gaps pertaining to supplemental free-form EAA, intact protein, and protein-containing mixed meal ingestion on MPS. We discuss the fundamental role of whole-body protein balance and highlight the importance of comprehensively assessing whole-body and muscle protein kinetics when evaluating the anabolic potential of varying protein feeding formats during energy deficit

Effects of high versus standard essential amino acid intakes on whole-body protein turnover and mixed muscle protein synthesis during energy deficit: A randomized, crossover study

© 2020 Background & aims: Consuming 0.10–0.14 g essential amino acids (EAA)/kg/dose (0.25–0.30 g protein/kg/dose) maximally stimulates muscle protein synthesis (MPS) during energy balance. Whether consuming EAA beyond that amount enhances MPS and whole-body anabolism following energy deficit is unknown. The aims of this study were to determine the effects of standard and high EAA ingestion on mixed MPS and whole-body protein turnover following energy deficit. Design: Nineteen males (mean ± SD; 23 ± 5 y; 25.4 ± 2.7 kg/m2) completed a randomized, double-blind crossover study consisting of two, 5-d energy deficits (−30 ± 4% of total energy requirements), separated by 14-d. Following each energy deficit, mixed MPS and whole-body protein synthesis (PS), breakdown (PB), and net balance (NET) were determined at rest and post-resistance exercise (RE) using primed, constant L-[2H5]-phenylalanine and L-[2H2]-tyrosine infusions. Beverages providing standard (0.1 g/kg, 7.87 ± 0.87 g) or high (0.3 g/kg, 23.5 ± 2.54 g) EAA were consumed post-RE. Circulating EAA were measured. Results: Postabsorptive mixed MPS (%/h) at rest was not different (P = 0.67) between treatments. Independent of EAA, postprandial mixed MPS at rest (standard EAA, 0.055 ± 0.01; high EAA, 0.061 ± 0.02) and post-RE (standard EAA, 0.055 ± 0.01; high EAA, 0.065 ± 0.02) were greater than postabsorptive mixed MPS at rest (P = 0.02 and P = 0.01, respectively). Change in (Δ postabsorptive) whole-body (g/180 min) PS and PB was greater for high than standard EAA [mean treatment difference (95% CI), 3.4 (2.3, 4.4); P = 0.001 and −15.6 (−17.8, −13.5); P = 0.001, respectively]. NET was more positive for high than standard EAA [19.0 (17.3, 20.7); P = 0.001]. EAA concentrations were greater in high than standard EAA (P = 0.001). Conclusions: These data demonstrate that high compared to standard EAA ingestion enhances whole-body protein status during underfeeding. However, the effects of consuming high and standard EAA on mixed MPS are the same during energy deficit. Clinical trial registry: NCT03372928, https://clinicaltrials.gov