Summary. The effects of a hypercaloric high carbohydrate diet on lipolysis and esterification were studied in biopsy samples of adipose tissue obtained from 5 healthy subjeets. Overfeeding with carbohydrate enhanced the rate of esterification of free fatty acids (FFA) without any alteration in the rate of lipolysis. The release of FFA from adipose tissue was inhibited. These observations indicate that the utilization of glucose and FFA by adipose tissue for the synthesis of triglycerides was facilitated during weight gain on a high carbohydrate diet.