Milk ingredients may increase weight in kids

The effect of milk proteins in adolescents is unclear. The objective of a December 1st Journal Nutrition study was to test whether milk and milk proteins reduce body weight, waist circumference, plasma insulin, and insulin secretion in overweight adolescents aged 12–15 years. They were randomized to 1 liter per day of skim milk, whey, casein, or water for 12 weeks. All milk drinks contained 35 grams protein per liter. 

The researchers found greater BMI at 12 weeks in the skim milk, whey, and casein groups compared with the water and pretest control groups. These data suggest that high intakes of skim milk, whey, and casein increase adverse markers in overweight adolescents and that whey and casein increase insulin secretion. Whether the effect on body weight is primary or secondary to the increased insulin secretion remains to be elucidated.