Body type can influence the way you respond to dieting. In general, ectomorphs (linear build, lower body fat, slender arms and legs) tend to have faster metabolic rates and are less tolerant of more restrictive meal plans. Mesomorphs (athletic build, medium body fat, strong arms and legs) tend to respond best to resistance training as part of their program, especially on Up-Adjust meal plans. Endomorphs (stocky build, more body fat, thick arms and legs) will often have to spend more time on more restrictive meal plans to reach their goal weight. Aerobic exercise plays a key role in maximizing results for endomorphs looking to reduce body fat.