The Atkins Diet is one of the most longstanding and highly popularized diets out there. The foundation of the diet is based upon avoidance of carbohydrates, without restricting calorie intake per se. It’s extremely restrictive in carbohydrate intake in the beginning phase at only 20g per day. From there, there is an eventual increase in carb allowance into the ‘life long’ maintenance phase.
(For a detailed review of the phases of Atkins, the Mayo clinic has written a nice summary which you can access here. )
Atkins has been studied in clinical trials, with some conflicting results. One clinical trial showed Aktins to be superior to other diets for weight loss at one year. However, another randomized controlled study published in the New England Journal of Medicine showed that, compared to a low calorie/high carb/low fat diet, there was no difference in weight at one year. Another clinical trial comparing Atkins vs Zone vs Ornish vs Weight Watchers found no difference in weight loss at 1 year – BUT – they found that there was more weight loss seen in people who stuck to the program – regardless of which of the 4 diets they were assigned to.
Because the Atkins diet can theoretically allow for unrestricted intake of high fat foods, there have been concerns raised that it may have a negative impact on cardiac risk factors like cholesterol levels, but the overall balance of the studies seems to show that this is not the case. That being said, the usual benefit in these risk factors that is seen with weight loss does not seem to be seen with Atkins either.
Again, I ask the bottom line question: Is this a permanent lifestyle change? The answer, for most people, is no. A high frequency of side effects are reported on the Atkins diet due to its low carb nature, such as headache, dizziness, weakness, fatigue, and constipation. It is also logistically very difficult to avoid carbs to this extent over the long term. It’s not appropriate for people with kidney problems or women who are pregnant or breastfeeding. A very careful discussion with your doctor is necessary before starting and while on Atkins, particularly for anyone on diuretics or treatment for diabetes.