How is it when bodybuilders are cutting they have more them ample amount of caffeine in their diet yet get well down to such as 6-8% body fat, caffeine is a stimulant, increases heart rate etc.
Increasing fat stores, I'm not convinced about that !
The body will not convert body fat into energy if it is also converting food you have just eaten into energy. It has no need to nor the capacity to do so. While the presence of insulin does delay the body restarting the use of body fat it is not significant. Even with high insulin the body can still burn fat through the Citric Acid Cycle anyway.
The body is only going to resort to burning body fat if there is no fresh energy coming into the body. As long as you eat less than your body needs you will burn body fat.