A comparison of low-carbohydrate vs. high-carbohydrate diets:: Energy restriction, nutrient quality and correlation to Body Mass Index

Objectives: To evaluate free-living adults' diets that ranged from very low to high amounts of carbohydrate for their energy content. nutritional quality and correlation to Body Mass Index. Methods: Adults ages 19 years and older, who had complete dietary intake data on day-1 of the USDA's 1994 to 1996 Continuing Survey of Food Intakes by Individuals (CSFII 1994-1996), were divided into four groups-very low. low. moderate and high carbohydrate- based on the percent total energy from carbohydrate. Mean energy, nutrient, food intakes and Body Mass Index values were compared among the groups. SUDAAN software package was used for the data analysis and pair-wise mean comparisons (p < 0.05). Results: The high-carbohydrate diet was lower in energy and energy density (number of kilocalories per gram of total amount of food consumed) than the other three diets. Macronutrient composition varied significantly among all the four groups. Nutrient density (amount of nutrient per 1,000 kilocalories of energy consumed) of vitamin A, carotene, vitamin C, folate, calcium, magnesium and iron increased and that of vitamin B 12 and zinc decreased with an increase in the percent total energy from carbohydrate. The high-carbohydrate group ate more of low-fat foods, grain products and fruits. This group also had the lowest sodium intake. Adults eating a high-carbohydrate diet are more likely to have Body Mass Index values below 25. Conclusion: A study of diets of free-living adults in the U.S. showed that diets high in carbohydrate were both energy restrictive and nutritious and may be adopted for successful weight management.