The Consistency in Macronutrient Oxidation and the Role for Epinephrine in the Response to Fasting and Overfeeding.
In humans, dietary vs intraindividual determinants of macronutrient oxidation preference and the role of the sympathetic nervous system (SNS) during short-term overfeeding and fasting are unclear.



To understand the influence on metabolic changes of diet and SNS during 24 hours of overfeeding.



While residing on a clinical research unit, 64 participants with normal glucose regulation were assessed during energy balance, fasting, and four 24-hour overfeeding diets, given in random order. The overfeeding diets contained 200% of energy requirements and varied macronutrient proportions: (1) standard (50% carbohydrate, 20% protein, and 30% fat); (2) 75% carbohydrate; (3) 60% fat; and (4) 3% protein.



Twenty-four-hour energy expenditure (EE) and macronutrient oxidation rates were measured in an indirect calorimeter during the dietary interventions, with concomitant measurement of urinary catecholamines and free cortisol.



EE decreased with fasting (-7.7% ± 4.8%; P < 0.0001) and increased with overfeeding. The smallest increase occurred during consumption of the diet with 3% protein (2.7% ± 4.5%; P = 0.001) and the greatest during the diet with 75% carbohydrate (13.8 ± 5.7%; P < 0.0001). Approximately 60% of macronutrient oxidation was determined by diet and 20% by intrinsic factors (P < 0.0001). Only urinary epinephrine differed between fasting and overfeeding diets (Δ = 2.25 ± 2.9 µg/24h; P < 0.0001). During fasting, higher urinary epinephrine concentrations correlated with smaller reductions in EE (ρ = 0.34; P = 0.01).



Independent from dietary macronutrient proportions, there is a strong individual contribution to fuel preference that remains consistent across diets. Higher urinary epinephrine levels may reflect the importance of epinephrine in maintaining EE during fasting.
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.
Karyne Lima
KL
Vinales
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.|Department of Geriatrics and Aging Research, University Hospital Zurich, 8091 Zurich, Switzerland; and.
Mathias
M
Schlögl
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.
Paolo
P
Piaggi
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.
Maximilian
M
Hohenadel
Johns Hopkins School of Medicine, Baltimore, Maryland 21205.
Alexis
A
Graham
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.
Susan
S
Bonfiglio
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.
Jonathan
J
Krakoff
Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, Arizona 85014.
Marie S
MS
Thearle
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004734:Energy Metabolism / Q000187:drug effects*; D004837:Epinephrine / Q000652:urine*; D005215:Fasting / Q000502:physiology*; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D044343:Overnutrition / Q000503:physiopathology*; D010084:Oxidation-Reduction; D011379:Prognosis; D055815:Young Adult
D015415:Biomarkers; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D004837:Epinephrine