An unbiased ketogenic diet tweetorial: I'm an endocrinologist treating individuals with obesity & diabetes. I've done research on effects of ketogenic diets in mice. I have no interest in any entities promoting these diets. Information is intended to educate the curious.
Ketogenic diets (KD) aim at achieving “ketosis.” Ketosis can occur naturally with any successful weight loss regimen. Ketosis is enhanced with fasting or when carbohydrates are limited. During ketosis fat is broken down into fatty acids, which are then broken down to ketones.
KD is not new. Dr. Atkins developed it 40 years ago as a diet that would be helpful for weight loss and glucose control in people with type II diabetes. With regard to weight loss, his theory was that ketosis would decrease hunger and help with the dieting.
The newly popularized “keto” diets are very similar to Atkins. The both restrict carbs. Possibly "keto" restricts protein a bit more than Atkins but meat is meat. Vegetarian KD is possible, but very hard.
KD eliminates carbs: potatoes, flour, rice, pasta, bread out. So are most fruits. Vegetables such as corn and tomatoes are out. Some people have to limit protein as well and may not be able to eat nuts. Most green vegetables are OK because carbohydrate/sugar content is very low.`
Some people can’t eat cheese because it may have too much protein. The same for nuts. A lot of information on what you can and can’t eat is on this website: atkins.com/how-it-works/a…
When eating KD, appetite may decrease so people may eat less. Some calories are also lost in the urine. In mice, eating KD leads to increased metabolic rate, but there’s no data this happens in humans.
When eating KD & losing weight, both dietary fat & body fat are burned to make ketones. Success with diet improves if people use “ketostix” to measure ketones in the urine as a “positive reinforcement to stay on the diet. If there’s no ketosis, there’s too much carb or protein.
Do people lose weight? Some lose huge amounts. Weight loss depends on how well one can stay on the diet and how easy it is to get ketotic. If someone needs to give up fruit and cheese but loves these items, it may be very hard to maintain the diet long-term.
When tested side by side with other diets, KD was somewhat more effective for weight loss compared standard calorie restriction with more carbs. However, differences between diets at the time of maximal weight loss (6 mos) were in the range of 5 kilograms (11 pounds).
Maintaining a KD diet also depends on food environment. If family members are normal weight and like to eat carbs, KD diets are going to be very difficult. Personal incentives and goals for weight loss also matter. Those who need to lose 15 pounds may find easier alternatives.
In contrast, for those with significant obesity and diabetes eating KD may help with both weight loss and lead to improved blood sugar control and in some cases decreased need for medications. @virtahealth has published data on this in the medical literature.
Are KD diets safe? Mostly yes. They are used with some success to treat seizures in kids who don’t respond to medications. KD is widely used in the “community” and some people have exceptionally successful weight loss.
If one you are going to try the diet, cholesterol and triglycerides should be checked before and after 6 weeks to be sure they don’t go up. Most people don’t have a problem.
For someone pregnant /planning pregnancy, this is NOT a tested diet. There is no data, one way or another that being ketotic all the time is safe. When nursing, ketones go into breastmilk. There’s no data on what ketones might do to an infant/toddler.
If otherwise healthy and aiming for weight loss, Atkins/keto may be worth trying. However no diet breaks the laws of physics. To lose weight one needs to eat fewer calories than one uses. KD works when an individual finds it easier to eat less on ketogenic diets.
For normal weight/a bit overweight, otherwise healthy people there is no advantage to being always ketotic. The many claims on health benefits for KD beyond weight loss are without hard evidence. However limiting carbs is a good idea because carbs seem to enhance weight gain.
For weight loss, especially in the 10-30 pound range, “Paleo diets” or “Zone diets” or Mediterranean diets or the 5/2 diet are potential alternatives. The best diet is one an individual can stick to and lose weight on.
