Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/12/2002
Publication Date: 2/19/2003
Citation: TREUTH, M.S., SUNEHAG, A.L., TRAUTWEIN, L.M., BIER, D.M., HAYMOND, M.W., BUTTE, N.F. METABOLIC ADAPTATION TO HIGH FAT AND HIGH CARBOHYDRATE DIETS IN CHILDREN. AMERICAN JOURNAL OF CLINICAL NUTRITION. 2003. V. 77. P. 479-489. Interpretive Summary: Obesity is greatly increasing in the United States. This is particularly unfortunate because it bodes ill for the development of serious diseases like diabetes, and increases the risk of heart attack and stroke. These days, American children and adults are eating much bigger meals, snacking more often on items without any nutritional value, and, in general, indulging in more high-fat, high-sugar foods than they did a generation ago. Studies have shown that if an adult experiences metabolic difficulty adapting to a high-fat or high-carbohydrate diet, that may present a risk factor for developing obesity and diabetes. However, these studies have not been done in children. We wanted to find out whether a representative group of healthy children would be able to adapt appropriately to a high-fat, high-carbohydrate diet. Therefore, we studied a group of children and adolescents, and took numerous types of measurements to determine their metabolic responses to high-fat or high-carbohydrate diets. Our results le us to conclude that healthy, normal-weight children are able to adapt appropriately to either a high-fat or a high-carbohydrate diet. These findings are highly useful in the scientific exploration of the causes of obesity, one of our biggest health problems not only in this country but worldwide.
Technical Abstract: Background: Difficulty adapting to high-fat and high-carbohydrate diets may predispose children to obesity and diabetes. Hypothesis: Children have the metabolic flexibility to adapt to high-fat and high-carbohydrate diets through changes in substrate utilization. Design: A random, cross-over study was used to test high-fat/low-carbohydrate (HF/LC) (55/30% of energy) )and low-fat/high-carbohydrate (LF/HC) (25/60% of energy) diets in healthy children. In Protocol 1, 24 children were randomly assigned to LF/HC or HF/LC diets. In Protocol 2, 12 adolescents were randomized to LF/HC diet with 11% or 40% of carbohydrate as fructose. Energy expenditure, nonprotein respiratory quotient RQ (NPRQ) and substrate utilization were measured using 24-h calorimetry after 7-d diet equilibration. Tests were performed to determine the effects of sex, puberty status (Tanner staging), body fat (DXA), intra-abdominal fat (IAF)(MRI), and fitness (O2peak) on substrate utilization. Fuel utilization was not affected by puberty, % body fat, IAF or fitness. Energy expenditure was not affected by diet in either protocol. In Protocol 1, NPRQ, carbohydrate and fat utilization were affected by diet (P=0.001) and sex (P=0.005). NPRQ and carbohydrate utilization increased on the LF/HC diet. NPRQ decreased and fat utilization increased on the HF/LC; however, changes in fuel utilization were less pronounced in girls than boys. In Protocol 2, the children adapted appropriately to the LF/HC diet; net carbohydrate utilization was slightly lower and net fat utilization was slightly higher during fasting (P=0.01) and into the subsequent feeding period (P=0.05). Conclusions: Healthy, nonobese children adapt appropriately to high-fat and high-carbohydrate diets.