The Atkins Diet, a type of diet known as ketogenic -- where you burn fatty acids as your primary source of energy instead of sugar or amino acids. The diet functions in several phases, with the first phase, Induction, restricting your intake of many foods. You must avoid many things during this period, but this does not include caffeine. Consult a health care practitioner before beginning any dietary program.
A ketogenic diet is based on a high fat intake, slightly higher protein intake and extremely limited carbohydrates. If you consume non-fibrous carbohydrates, your body will burn them preferentially, making it impossible for you to remain in ketosis. The same holds true if you consume an excessive amount of protein, which will get broken down into amino acids, then converted to sugar. Usually, at least 60 percent of your calories must come from fat to maintain dietary ketosis.
Induction is the phase in the Atkins Diet where you push yourself into ketosis. This is a two- or three-week period where your body begins to make the shift from burning glycogen to burning ketones, or free-floating fatty acids as its primary source of energy. This, for many, is the most difficult part of the diet, as many processes of your body run on glycogen, or sugar. The dropping of your sugar levels can initially cause hunger pangs and mood swings, but consuming sugar to alleviate this essentially puts you back where you started.
Caffeine is a compound belonging to the category known as methylxanithines, which relates to its structure. Caffeine functions as a stimulant, and is commonly consumed in many forms. Caffeine also functions as a diuretic, or substance that depletes your water reserves. This requires caffeine consumed in excess, and a study published in the December 2003 edition of the "Journal of Human Nutrition and Dietetics" showed that caffeine consumed in beverages as part of a regular diet posed no danger from extreme water loss.
Caffeine During Induction
While caffeine exhibits no specific effect on ketosis, other issues arise during the induction phase of the Atkins Diet. The biggest issue for most is dehydration, and during this phase you do not need any extra help losing water. While the diuretic effects of a single cup of coffee are not inherently harmful, you need to drink more water and less diuresis-inducing beverages. There is no actual evidence to support the statements that caffeine will limit your ability to achieve ketosis.