Before you get your hopes up, this was declared a myth and does not work, for obvious reasons. Chocolate has huge amounts of fat and sugar, even if it does have its own share of health benefits (like lowering blood pressure, preventing heart disease, and declogging arteries through a lion’s share of anti-oxidants). So, the question begs to be asked”why was it considered to be a diet food, anyway?”
Because a few studies show that chocolate increases the metabolism and improves the body’s fat burning process. So crushed and extracted and processed into relatively low-sugar powders and pills, the dream was that we could stay on our diet and get our chocolate fix. Alas, the results are questionable. Whatever those studies were, they have yet to be repeated in an independent clinical trial.
To be fair, the product was originally sold as a healthy, low-calorie snack, and was never meant to be a wonder diet drug. Chocolate as a complete diet program was probably started by users who took its claims to the extreme.