About

Heather J. Leidy, PhD, is an Associate Professor at the University of Texas at Austin with a joint appointment in the Department of Nutritional Sciences and the Department of Pediatrics through the Dell Medical School. She also serves as the Director of the Research Interest Groups through the American Society of Nutrition and is a member of the 2020 Dietary Guidelines Advisory Committee. Her background includes a post-doctoral fellowship in Physiology with an emphasis in exercise endocrinology and metabolism at Penn State University, and a BS in Biology from Shippensburg University. As a nutritional physiologist, Dr. Leidy examines the effects of dietary protein quantity, quality, and timing on metabolic, hormonal, and neural signals that promote satiety, healthy eating behavior, and weight management across the lifespan. Her research has led to the development of dietary strategies for the prevention and treatment of obesity and type 2 diabetes. Her current research focuses on the impact of consuming a high-protein breakfast on satiety, glycemic control, and weight management in overweight young people. She employs various procedures within her human clinical studies, including blood sampling of gut-derived hormones, functional MRI brain scans, continuous glucose monitoring, and sleep assessments. Dr. Leidy has authored over 60 original research publications and has delivered more than 100 invited research talks. Her work provides evidence supporting the consumption of increased, high-quality protein, particularly at breakfast, as a key dietary strategy for improving appetite regulation, glycemic control, and weight management in young populations. Her research aims to elucidate mechanisms by which a protein-rich breakfast may aid in the treatment of obesity and prevention of type 2 diabetes.

Research topics

• Medicine
• Internal medicine
• Endocrinology
• Food science
• Biology
• Environmental health
• Physical therapy
• Demography
• Gerontology

Selected publications

• A Modern Take on Protein Nutrition Meets Evolving Consumer Perceptions

  Journal of Nutrition · 2026-03-11

  articleOpen access

  Protein is an essential nutrient that supports many critical aspects of health across the lifespan. The scientific report from the 2025 Dietary Guidelines Advisory Committee found that certain subgroups, particularly adolescent females, young females, and older adults, are at a higher risk of not consuming the recommended amount of dietary protein. The new 2025-2030 Dietary Guidelines for Americans prioritize a serving of protein with each meal and recommend a healthy range of protein intake for adults of 1.2-1.6 g protein per kg body weight per day. Data from the 2025 Food and Health Survey conducted by the International Food Information Council show that consumer interest in protein has risen dramatically in the last decade, as consumers increasingly report following a high-protein diet and use the protein content of food as a marker for healthfulness. Despite an increase in consumer interest in protein, there is still a limited understanding of how healthcare professionals can effectively support increased intake of protein sources among at-risk populations. Past research shows that protein-fortified foods can be used to supplement protein intake in randomized controlled trials that have demonstrated positive health outcomes in study participants. However, many of these foods are considered highly processed, which leads to debate regarding their role in healthy dietary patterns. This perspective examines consumer perceptions around protein intake and highlights the role of healthcare professionals in providing tailored guidance on protein food choices.

  PublisherDOI

• Proceedings from Nourish Now: A science dialogue on improving adolescent health through nutrition

  Critical Reviews in Food Science and Nutrition · 2026-03-25 · 1 citations

  article

  on May 2, 2024.

  PublisherDOI

• The effect of consuming diets containing beef compared with plant-based beef substitute on human milk composition in the study of nutrition in postpartum and early-life (SUPER) randomized crossover feeding trial

  American Journal of Clinical Nutrition · 2025-11-17

  articleOpen access

  BACKGROUND: Ultraprocessed foods (UPFs), including plant-based meat substitutes, are marketed as healthy alternatives to whole foods. However, little evidence exists regarding their effects on human milk composition, particularly how dietary UPFs might alter human milk fatty acids. OBJECTIVES: We tested whether replacing beef with an ultraprocessed plant-based beef substitute alters human milk fatty acid profiles. METHODS: In a double-blind, randomized, crossover feeding trial, 17 lactating females whose infants were fed only their milk completed 2 6-d diet phases separated by 6-d washout periods. Participants consumed 339 g (12 oz) daily of beef or plant-based substitute, depending on the diet phase. All meals were prepared in a metabolic kitchen and fully provided. Dietary compliance exceeded 95%. The final human milk samples collected on day 6 of each condition were analyzed for 27 fatty acids. Mean differences in fatty acid percentages were assessed with independent and paired t-tests for intervention food and human milk samples, respectively. Maternal weight, satiety, glucose response, and infant intake were also measured. RESULTS: Human milk collected during the substitute diet contained higher levels of tropical oil-derived medium-chain saturated fatty acids, such as lauric acid (12:0: 9.32 ± 1.8 compared with 4.47 ± 1.82, P < 0.001) and lower levels of long-chain polyunsaturated fatty acids (LCPUFAs), including arachidonic acid (20:4n-6: 0.35 ± 0.06 compared with 0.41 ± 0.06, P < 0.001) compared with milk form the beef diet. No significant differences were observed in maternal weight, satiety, glucose response, or infant intake. CONCLUSIONS: Replacing beef with plant-based UPF changed human milk fatty acid composition, reducing LCPUFAs and increasing tropical oil-derived saturated fats. These shifts may have implications for infant neurodevelopment and immune function, highlighting the need to distinguish between nutrient-equivalent and biologically equivalent foods in postpartum dietary guidance. This trial was registered at www. CLINICALTRIALS: gov as NCT06082921.

  PublisherDOI

• Welcome to The Journal of Nutritional Physiology

  The Journal of Nutritional Physiology · 2025-04-01

  articleOpen accessSenior author

  Nutritional physiology is the study of how the body processes food and utilises nutrients to maintain health, support growth, and perform bodily functions. The field has evolved over centuries, with key discoveries shaping our understanding of metabolism, digestion, and the role of nutrients in health, although it is hard to precisely identify its roots. Hippocrates, often touted as the father of modern medicine, clearly recognised the important link between diet and health, reportedly quoting

  PublisherOA PDFDOI

• A randomized controlled trial of once-weekly semaglutide for limiting post-smoking cessation weight gain in smokers with overweight/obesity: Study protocol

  Contemporary Clinical Trials · 2025-06-18 · 3 citations

  article
  PublisherDOI

• Middle-school students who consumed school breakfast perform better on tasks assessing cognitive flexibility and executive function

  Nutrition Research · 2025-11-20

  article1st authorCorresponding
  PublisherDOI

• Examining the Direct and Indirect Effects of Postprandial Amino Acid Responses on Markers of Satiety following the Acute Consumption of Lean Beef-Rich Meals in Healthy Women with Overweight

  Nutrients · 2024-05-31 · 1 citations

  articleOpen accessSenior authorCorresponding

  The consumption of protein-rich foods stimulates satiety more than other macronutrient-rich foods; however, the underlying mechanisms-of-action are not well-characterized. The objective of this study was to identify the direct and indirect effects of postprandial amino acid (AA) responses on satiety. Seventeen women (mean ± SEM, age: 33 ± 1 year; BMI: 27.8 ± 0.1 kg/m2) consumed a eucaloric, plant-based diet containing two servings of lean beef/day (i.e., 7.5 oz (207 g)) for 7 days. During day 6, the participants completed a 12 h controlled-feeding, clinical testing day including repeated satiety questionnaires and blood sampling to assess pre- and postprandial plasma AAs, PYY, and GLP-1. Regression and mediation analyses were completed to assess AA predictors and hormonal mediators. Total plasma AAs explained 41.1% of the variance in perceived daily fullness (p &lt; 0.001), 61.0% in PYY (p &lt; 0.001), and 66.1% in GLP-1 (p &lt; 0.001) concentrations, respectively. Several individual AAs significantly predicted fluctuations in daily fullness, PYY, and GLP-1. In completing mediation analyses, the effect of plasma leucine on daily fullness was fully mediated by circulating PYY concentrations (indirect effect = B: 0.09 [Boot 95% CI: 0.032, 0.17]) as no leucine-fullness direct effect was observed. No other mediators were identified. Although a number of circulating AAs predict satiety, leucine was found to do so through changes in PYY concentrations in middle-aged women.

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• Changing the default meal option at university events to reduce harmful environmental impacts: Six randomized controlled trials

  Appetite · 2024-06-20 · 7 citations

  articleOpen access

  Animal agriculture is a leading contributor to greenhouse gas emissions and other harmful environmental impacts, which underscores the need to shift away from the consumption of animal-based products. One promising nudge intervention is making plant-based meals the default option, so we tested this approach at six different university events across four academic institutions for effecting sustainable dietary change. Event attendees pre-selected their meal on one of two randomly assigned RSVP forms: one with a plant-based default and one with a meal with meat default. The results from our randomized controlled trial showed that participants had a 43-percentage point greater probability of selecting the plant-based meal when it was indicated as the default option. This effect was similar across events and academic institutions, which indicates that this default intervention is generalizable and can be successfully implemented at university events. The combined effect of using plant-based defaults at these six events was an estimated reduction of 104,387 kg of CO2 emissions, 299.9 m2 of land use, 959.0 g of nitrogen use, and 259.5 g of phosphorus use, which represent roughly 45–46.2% reductions in harmful environmental impacts relative to the meals chosen when using a meat default. Given the significance and magnitude of these environmental benefits, our results support the widespread implementation of plant-based defaults for helping universities improve their sustainability.

  PublisherDOI

• A Diet Containing Animal Source Protein as Fresh, Lean Beef Is More Well Liked and Promotes Healthier Eating Behavior Compared with Plant-Based Alternatives in Women with Overweight

  Current Developments in Nutrition · 2024-07-14 · 3 citations

  articleOpen accessSenior authorCorresponding

  BackgroundDespite limited evidence from intervention trials, replacing animal-source protein-rich foods with plant alternatives continues to be recommended as part of a healthy dietary pattern.ObjectivesThe objective of this study was to examine whether a diet containing fresh, lean beef elicits greater satiety, reduces ad libitum food intake, and is more acceptable compared with a diet containing plant alternatives in women with overweight.MethodsSeventeen women with overweight (mean ± SEM, age: 33 ± 1 y; BMI: 27.8 ± 0.1 kg/m2) completed an acute, tightly controlled, crossover design study. Participants were provided with eucaloric, isonitrogenous diets (15% of daily intake as protein) containing either 2 servings/d of fresh lean beef (BEEF) or plant equivalents (PLANT) for 7 d/pattern. During day 6 of each pattern, the participants completed a 10-h controlled-feeding, clinical testing day, which included repeated appetite and satiety questionnaires and blood sampling to assess pre- and postprandial plasma peptide YY (PYY) and GLP-1 across the day. On day 7, the participants completed a free-living testing day in which they consumed their respective protein foods and were provided with additional carbohydrate- and fat-rich foods to consume, ad libitum, during each eating occasion. Energy and macronutrient composition were assessed. A 2- to 3-wk washout period occurred between patterns.ResultsNo differences in daily satiety were detected between patterns. During the ad libitum testing day, 24-h food intake was not different between patterns (BEEF: 2714 ± 219 compared with PLANT: 2859 ± 147 kcals/d), BEEF led to fewer carbohydrates consumed compared with PLANT (338 ± 34 compared with 370 ± 22 g/d, P < 0.05), especially as sugar (169 ± 73 g compared with 186 ± 57 g, P = 0.05). Furthermore, BEEF was more well liked (i.e., higher flavor, texture, and acceptability) compared with PLANT (all, P < 0.05).ConclusionsAlthough satiety was similar between patterns, the consumption of animal-source protein-rich foods, such as fresh and lean beef, was more well liked and resulted in voluntary reductions in total carbohydrate and sugar intake in middle-aged women with overweight during a single ad libitum testing day.This study was registered at clinicaltrials.gov as NCT02614729.

  PublisherOA PDFDOI

• Indices of Sleep Health Are Associated With Timing and Duration of Eating in Young Adults

  Journal of the Academy of Nutrition and Dietetics · 2024-04-30 · 12 citations

  articleOpen access
  PublisherDOI

Recent grants

• NIH Grant M01RR023940

  NIH · $13.2M · 2011

Frequent coauthors

• Richard D. Mattes

  Purdue University West Lafayette

  115 shared

• Thomas P. Wycherley

  University of South Australia

  81 shared

• Arne Astrup

  Novo Nordisk Foundation

  81 shared

• Stephen C. Woods

  81 shared

• Natalie D. Luscombe‐Marsh

  Diabetes Australia

  81 shared

• Peter Clifton

  Royal Adelaide Hospital

  81 shared

• Margriet S. Westerterp‐Plantenga

  Maastricht University

  81 shared

• W. W. Campbell

  Purdue University West Lafayette

  48 shared

Labs

• Heather Leidy LaboratoryPI

Awards & honors

• Director of the Research Interest Groups through the America…
• Member of the 2020 Dietary Guidelines Advisory Committee