Does Your Morning Coffee Really Make You Eat Less?

MedicalResearch.com Interview with:
Coffee being poured Coffee pot pouring cup of coffee. copyright American Heart Association
Leah Panek-Shirley, PhD

Assistant Professor
Buffalo State College
Health, Nutrition, and Dietetics
Houston Texas

MedicalResearch.com: What is the background for this study? What are the main findings?


Response:
The findings of existing previous research evaluating the effects of caffeine on appetite and eating are equivocal.

This study evaluated the effects of no (0 mg/kg body weight, e.g. placebo), low (1 mg/kg body weight), and moderate (3 mg/kg body weight) doses of caffeine in juice on appetite and eating in the laboratory and under free-living conditions.

While this study identified a small decrease (about 70 calories) in caloric intake after consuming the low (1 mg/kg) dose of caffeine in the laboratory at breakfast, this difference did not persist throughout the entire day.  In addition, there were no differences in hunger, fullness, thirst, or desire to eat as a result of caffeine.

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Intranasal Oxytocin Reduced Calorie Consumption in Men

Elizabeth A. Lawson, M.D., M.M.Sc. Assistant Professor of Medicine Harvard Medical School Director, Interdisciplinary Oxytocin Research Program Neuroendocrine Unit Massachusetts General Hospital Boston, MA 02114MedicalResearch.com Interview with:
Elizabeth A. Lawson, M.D., M.M.Sc.
Assistant Professor of Medicine
Harvard Medical School
Director, Interdisciplinary Oxytocin Research Program
Neuroendocrine Unit Massachusetts General Hospital
Boston, MA 02114

Medical Research: What is the background for this study? What are the main findings?

Response: Oxytocin is a hormone produced in the brain that has been shown to reduce food intake in animal studies. The role of oxytocin on appetite and food consumption in humans is not well understood. We therefore performed a randomized, placebo controlled cross-over study of single dose administration of intranasal oxytocin (Syntocinon, Novartis) in healthy men. Subjects presented fasting in the early morning and were randomized to receive 24 IU intranasal oxytocin or placebo. They selected breakfast from a menu and were offered double portions. The caloric content of the food they ate was calculated. They returned for a second visit, which was the same except for this time, they received the other treatment (placebo or oxytocin). There was no difference in how much food the men reported eating in the three days leading up to each of the study visits. On average, the men ate 122 fewer calories and about 9 grams less fat after receiving oxytocin compared to placebo. There was also evidence that oxytocin resulted in greater use of fat as a fuel for the body, and improved insulin sensitivity.

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Protein Suppresses Appetite More Than Fat or Carbohydrates

Anestis Dougkas, MSc, PhD Food for Health Science Centre Lund University Lund, SwedenMedicalResearch.com Interview with:
Anestis Dougkas, MSc, PhD
Food for Health Science Centre
Lund University Lund, Sweden

MedicalResearch: What is the background for this study?

Dr. Dougkas: There has been an increased interest in the macronutrient profile of diets and meals as a factor that influences appetite. Dietary protein is considered as the most satiating macronutrient, yet there is little evidence on whether the effects observed are attributed to the protein or to the concomitant manipulation of carbohydrates and fat. The aim was to examine the effect of consumption of beverages varying in macronutrient content on appetite ratings, energy intake and appetite-regulating hormones.

MedicalResearch: What are the main findings?

Dr. Dougkas: Increased protein content suppressed more average appetite than carbohydrate and fat with a more pronounced effect of protein intake on subjective ratings of prospective consumption. Protein was also the most influential macronutrient for postprandial glucagon like peptide-1 (GLP-1, an appetite- suppressing hormone) response. This appetite-suppressing effect of protein was independent of the changes in fat and carbohydrates.
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Brain Enzyme May Regulate Appetite For Sugar

MedicalResearch.com Interview with:
Dr James Gardiner

Reader in Molecular Physiology
Imperial College Hammersmith Campus
London 0NN

Medical Research: What is the background for this study? What are the main findings?

Response: It is well known that glucose is a preferred food and is consumed in preference to other nutrients. Food intake is controlled by the brain in part this it is regulated by part of the brain called the hypothalamus.   Glucokinase is an important component of glucose sensing and is expressed in the hypothalamus and specifically in the arcuate nucleus. A hypothalamic mechanism regulating glucose intake has not previously been identified.

Using a rodent model we demonstrated that increasing glucokinase activity in the arcuate nucleus increased food intake and body weight. If glucose was available as separately then glucose intake is increased but not weight. Decreasing glucokinase activity in the arcuate nucleus had the opposite effect, reducing glucose intake when it was available.   Our results suggest that glucokinase controls glucose appetite and hence the amount of glucose consumed. This is the first time a mechanism controlling the intake of a specific nutrient has been described.

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Poor Appetite in Elderly Increases Mortality Risk

Professor Mark L. Wahlqvist, M.D., Ph.D. Institute of Population Health Sciences, National Health Research Institutes, Taiwan National Defense Medical Center, School of Public Health, Taiwan Monash Asia Institute, Monash University Melbourne, AustraliaMedicalResearch.com Interview with:
Professor Mark L. Wahlqvist, M.D., Ph.D.
Institute of Population Health Sciences, National Health Research Institutes, Taiwan
National Defense Medical Center, School of Public Health, Taiwan
Monash Asia Institute, Monash University Melbourne, Australia

Medical Research: What are the main findings of the study?

Prof. Wahlqvist: Poor appetite and dietary quality as judged by diversity separately (each by about 50%) and together (by about 80%) increase the mortality risk in older persons living in the community.
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Dietary Fiber: Potential Mechanism of Appetite Suppression Discovered

Professor Gary Frost PhD RD Head of the Nutrition and Dietetic Research Group NIHR Senior Investigator Division of Diabetes, Endocrinology and Metabolism Faculty of Medicine Imperial College Hammersmith Campus London W12 ONNMedicalResearch.com Interview with:
Professor Gary Frost PhD RD
Head of the Nutrition and Dietetic Research Group
NIHR Senior Investigator
Division of Diabetes, Endocrinology and Metabolism
Faculty of Medicine Imperial College Hammersmith Campus
London W12 ONN

MedicalResearch.com: What are the main findings of the study? 

Prof. Frost: That acetate that is derived from the fermentation of dietary fiber in the colon by the microbiota is taken up by the hypothalamus in the brain.  In the hypothalamus the way the cells metabolize acetate creates a signal that suppresses appetite
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