Veggie Blog

The Atkins diet is one of the best-known low-carbohydrate plans, and the old version of this post listed its benefits and its few downsides. It also said that low-carb eating has been “scientifically proven” to improve insulin sensitivity, blood pressure and blood insulin, and that dieters lose less muscle than on low-fat plans. I could not support those claims, so this rewrite goes back to the studies.

What are the possible benefits?

A 2013 meta-analysis in the British Journal of Nutrition looked at 13 trials with 1,415 people who followed a very-low-carbohydrate diet or a low-fat diet for at least a year. The low-carb group lost about 0.9 kg (2 pounds) more on average, had lower triglycerides, a slightly lower diastolic blood pressure and higher HDL (“good”) cholesterol, but also higher LDL (“bad”) cholesterol. The authors described the differences as statistically significant but small in practical terms. A larger 12-month trial of 609 adults found no significant difference between a healthy low-carb and a healthy low-fat diet (6.0 kg lost compared with 5.3 kg), which fits the common advice that the best plan is usually the one you can keep following. See the meta-analysis abstract for the details.

Is it really “eat what you like”?

The old post argued that steak, butter and cream are a regular part of the plan, and that former dieters would enjoy the “forbidden” foods. That freedom is part of the appeal, but it is also the part doctors worry about. Harvard Health notes that these diets often look like plates piled with bacon, meat, eggs and cheese, and that the American Heart Association recommends about 13 grams of saturated fat a day (6 percent of a 2,000-calorie diet). A 20-week trial that fed people high-saturated-fat low-carb diets did not show worse heart-risk markers, but it was short, and how such diets affect heart attacks or strokes in the long run is unknown. Vegetables, nuts, fish and olive oil make a safer base than processed meat.

What are the downsides?

The first two weeks are the hardest. Cleveland Clinic says that “keto flu” symptoms (headache, fatigue, irritability, nausea, constipation or diarrhea) can appear two to seven days after you reach ketosis and last between two days and a month, usually somewhere in between. The old post said these effects are “transient” but that some people quit because of them, which is fair. Harvard Health adds that a strict ketogenic diet can raise LDL cholesterol, and that using it for a long time is linked to a higher risk of kidney stones, osteoporosis and gout. Low-fiber eating can also cause constipation, so keep non-starchy vegetables on the plate.

What about carb counting and your personal carb level?

The old post said some people can maintain weight on 90 grams of carbohydrate a day and others on 120. Atkins now says that most people’s personal carb tolerance is 40 to 120 grams of net carbs a day, and that you find yours in the later phases. Atkins has also renamed its plans, so the names of the phases may differ from the old ones. Our post on Atkins Diet basics explains the structure, and Atkins induction rules walks through the first two weeks.

Who should talk to a doctor first?

If you are pregnant or breastfeeding, have kidney disease or a history of disordered eating, or take medicine for diabetes, speak with your doctor before you start. The American Diabetes Association’s standards say that low-carb plans are not recommended for pregnant or lactating women, people with or at risk of disordered eating, or people with kidney disease, and that they should be used with caution with some diabetes medicines called SGLT2 inhibitors. Our guide to common mistakes Atkins dieters make helps you avoid the usual traps. Finally, the old post said “it works” for thousands of dieters, which is true for short-term weight loss, but the research shows that the long-term difference is small.