This could be because the body increases insulin secretion in anticipation that sugar will appear in the blood. When this doesn’t happen, blood sugar drops and hunger increases. Whether this chain of events regularly takes place is somewhat unclear. Something odd happened when I tested Pepsi Max though, and there are well-designed studies showing increased insulin when using artificial sweeteners.
At its core, burning fat comes down to the process of lipolysis—the breaking down of fat lipids, explains Seedman. This happens in the mitochondria of the muscles, or the powerhouses of the cells, responsible for generating the energy our cells need to do their jobs. Exercise has been shown to improve mitochondria function, which then promotes fat breakdown, Seedman adds. Plus, working out helps regulate pretty much all the hormones that optimize fat loss.