The Atkins Diet is one relatively popular weight loss method in which dieters consume very small quantities of carbohydrate, while relying predominantly upon protein and fat for energy. There are a number of chemical changes that take place in your body when you're on the Atkins Diet, some of which can cause a foul body odor.
The Atkins Diet
Dr. Robert Atkins popularized a method of weight loss now called the Atkins Diet with his book "Dr. Atkins Diet Revolution." The diet is based upon the controversial principles that when you consume carbohydrate, your body "loses" its ability to burn fat for energy, and that by consuming large quantities of fat and protein rather than carbohydrate, you can "retrain" the body to burn fat. As such, on the Atkins Diet, you eat very little carbohydrate -- typically less than 20 g per day in the early weeks of dieting.
During the early phase of the Atkins Diet, called the "induction phase," you limit carbohydrate intake so significantly that the body is forced to break down stored carbohydrate. Your liver and muscles store carbohydrate in the form of a molecule called glycogen, which breaks down into glucose, explain Drs. Reginald Garrett and Charles Grisham in their book "Biochemistry." The brain doesn't use protein or fat for energy; it requires glucose. As such, the induction phase of the Atkins Diet is designed to use your stored glycogen and then force your body to start burning fat.
Once you've used nearly all your stored glycogen, you enter a chemical state called ketosis. In this state, your cells make chemicals called "ketone bodies" from fats. While the brain runs primarily -- and most efficiently -- on glucose, it can use ketone bodies in an emergency. Ketone bodies have an odd odor to them; they're not unlike fingernail polish remover in their smell. Once you enter ketosis, it's common for others to smell ketone bodies on your breath and in your sweat, which can give you a foul, sickly-sweet odor.
Unfortunately, there's no way to prevent the foul odor that you're likely to develop after about two weeks on the Atkins Diet. This is because the purpose of the diet is to induce ketosis, and by definition, in ketosis you'll have ketone bodies circulating. The smell resolves nearly immediately once you begin consuming carbohydrate again, since you'll be once again providing your brain with glucose -- its preferred food -- and you'll stop producing ketones.