Abstract
I examined the physiological, renal, pulmonary, endocrine, and exercise effects of metabolic shifts due to very low-carbohydrate, high-protein diets. Although such diet regimes are popular and effective for acute weight loss, the nature and side-effects of the weight loss have not yet been fully described. Three contending hypotheses are caloric reduction, fat mass reduction via ketosis, and dehydration. 24 healthy male participants were used (mean age of 31.71 ± 1.68 years) in a parallel control group design at the California State University, Sacramento. All participants reduced their carbohydrate intake to < 5% of their daily total intake and had a significant reduction in plasma glucose (p<0.05). Ketones (p<0.005), microalbumin (p<0.05), urine volumes (p<0.05), and urinary pH (p<0.002 ) all showed significant changes from 24-hour urine samples. The clinical index ratio of blood urea nitrogen to creatinine also showed significant change for the dietary treatment group (p<0.05) indicating a dehydrated condition. Percent change in body weight was significantly correlated to the percent change of the blood urea nitrogen to creatinine ratio (r2 = 0.58, p<0.05) while not significantly correlated to either caloric reduction or percent change fat mass. The dietary group showed a significant reduction in their capacity for high-intensity exercise (p<0.05) and respiratory exchange ratio (p<0.001) during exercise. The goals of this report were to better understand the biological effects of these diets and their public health implications. Additionally, due to physiology's ability to interface with multiple biological disciplines, I also speculate on the ecological, ecophysiological, and conservation implications of metabolic shifts. In the following set of experiments I fundamentally altered nutrient stoichiometry by increasing the amount of nitrogen. The observed consequences may
have implications for how organisms acutely respond to environmental changes in nutrients (e.g. nitrogen and phosphorous).