Puberty is associated with a deterioration of blood glucose control in children with type 1 diabetes (T1D). The literature suggests that exercise improves homeostasis in adults with diabetes, but lack of time often precludes the performance of exercise. Besides, in earlier work, supplementation with glutamine, a nonessential amino acid, when administered prior to exercise, decreased overnight post-exercise blood glucose in adolescents with long-standing T1D, suggesting that glutamine increased insulin sensitivity or enhanced tissue glucose uptake. The purpose of the current study therefore was to determine the feasibility of a novel form of exercise (“exercise snacks,” that is, short bouts of exercise spread throughout the day) with or without a supplemental amino acid, glutamine, and its impact on blood glucose homeostasis and body composition in adolescents with T1D. Methods: Twelve sedentary adolescents with T1D (HbA1c 8.1 ± 0.6%) performed exercise snacks (6 × 1 min of resistance-based activities) 3 times daily for 3 months; in addition, they were randomized to consume a drink containing either placebo or glutamine (0.5 g/kg/day). Continuous glucose monitoring, HbA1c, and dual X-ray absorptiometry were obtained before and after 3 months of each intervention. Results: Exercise snacks were easy to perform and well tolerated and were associated with a 2.2% loss of body fat mass when both groups were analyzed together (p = 0.015) after 3 months, whereas the change in lean body mass was not significant (p = 0.21). Metabolic control (HbA1c and glucose sensor data) was unchanged as result of the intervention regardless of group, and total daily insulin dose did not decrease. Conclusion: Short bouts of exercise are sustainable over a 3-month period and can improve body composition in adolescents with poorly controlled T1D. Although metabolic control was unchanged as a result of the intervention regardless of group, this was a short-term intervention, hence assessment of metabolic impact will require long-term study.