Effects of short term modified carbohydrate diets on weight loss, urine ketone production, and urinary calcium excretion in free living overweight college students

The purpose of this study was to determine outcomes of low carbohydrate (LC) and moderate carbohydrate (MC) diets on weight loss, ketone production, and urinary calcium excretion in overweight college students. Twenty‐two students were randomly divided into two experimental periods of 14 days each. For the first 14 days, one half of the subjects (N=11) received a LC diet (30g carbohydrate/day with ad libitum intakes of protein and fat), while the other half of the subjects (N=11) received a MC diet (60g carbohydrate/day with ad libitum intakes of protein and fat). After 14 days, there was a cross over of the diets. Urinary calcium excretion, ketones, and body weight were assessed on the first day of the study and at the end of each experimental period. A 2x2 ANOVA revealed a significant weight loss within subjects over time for each experimental diet group (p< .01). However, over time there was no significant difference in weight loss between the diet groups (LC‐MC; MC‐LC). Participants in both diet groups (LC‐MC; MC‐LC) exhibited significant difference in urinary calcium excretion over time in each experimental period (p= 0.035). However, over time there was no significant difference in urinary calcium excretion between the diet groups. Type of diet did not influence urine ketone production. This research suggests that short term use of modified carbohydrate diets may promote weight loss and urinary calcium excretion.