Do you want an interesting life? Break the rules: walk backwards, hang your pictures upside-down, sleep during the day, party all night, every night, and drive on the wrong side of the road. Or just go keto!
Ketogenic diets (keto diets) take the traditional food pyramid and turn it on its head. Instead of relying on carbohydrates as the main source of nutritional energy, they recommend consumption of fats. Some low-carb diets allow moderate consumption of carbs (South Beach Diet, and The Zone Diet, for example); but at its most restrictive form, a ketogenic diet, such as the Atkin’s diet in its induction phase, limits carbohydrates to very low levels.
On a severe low-carb diet, the body shifts into a starvation mode. Liver cells start to metabolize fatty acids into ketone bodies. These ketone bodies are then released into the blood stream (ketosis) and serve as an alternative source of energy.
For ketosis to occur, the amounts of carbs in a diet need to be very low–about 5-10% of the total daily energy, or, in some people, less than 20 grams of carbohydrates a day. That means no bread, cakes, or any other bakery items; no grains; no sugar in any form; no chips or crackers; no high-sugar fruits. But it is okay to eat pork, beef, chicken, fish, seafood, eggs, avocado, strawberries, watermelon, leafy vegetables, and dark chocolate. Do you feel like egg and bacon for breakfast, chicken for lunch, and a steak for dinner? You go ahead and have it, but take into account that you can’t have a slice of toast, nor rice or French fries on the side, and that every hotdog you eat, will have to go down bun-less-ly, and without even a drop of ketchup.
A certain amount of protein is essential to maintain good health (the exact amount is still in debate). Therefore, in order to lose weight, one would have to decrease the intake of either one of the two other macronutrients–carbs, and fat. This is the basis for the ongoing war between those who believe in low-carb diets, and those who prescribe low-fat diets.
Does the Keto diet–a low-carb diet–work? In a meta-analysis published in the online journal PLoS ONE, Jonathan Sackner-Bernstein from ExVivos LLC, New York, analyzed a group of 17 controlled trials in which participants were randomized into either a low-carb diet, or a low-fat diet. Most of the 17 trials were short in duration, with twelve of them lasting for less than a year. Some diets called for caloric restriction and some didn’t. There were 1797 patients in total. And the results were significant. Both groups lost significant amount of weight. But participants on low-carb diets lost more weight than participants on low-fat diets (7.8 kg vs 5.9 kg). In this analysis, low-carb diets had a more beneficial effect on HDL (good cholesterol) and on triglyceride levels, while low-fat diets had a more beneficial effect on total cholesterol and on LDL (bad cholesterol).
A separate, non-randomized study, on patients with diabetes, compared a very-low-carb diet with a diet based on standard-diet recommendation. Participants on the standard-diet did not lose weight and had no improvement in their diabetes. In contrast, participants who were on the very-low-carb diet showed a significant reduction in weight (12% of body weight), and a significant improvement in their hemoglobin A1c which is a marker of the severity of diabetes. In addition, once on the low-carb diet, 94% of the participants who had been taking insulin before the trial, could either reduce the dose of insulin, or stop taking it altogether.
These results seem impressive. But on deeper examination, the results seem less convincing. The first article, by Jonathan Sackner-Bernstein, may be inconclusive due to the short duration of the studies that were included in the meta-analysis. The second study, on diabetic patients, suffered from two problems: First, it wasn’t a randomized study. And second, participants in the very-low-carb diet were provided with tools that weren’t available to participants in the other group: extensive counseling, access to a web-based application for bio-marker reporting and monitoring, and monitoring devices such as cellular-connected body weight scale, and a ketone meter.
What are the short-term side effects of ketogenic diets? What are the long-term effects of staying on such a diet? Going keto seems interesting. But is it as harmless as hanging your pictures upside-down, or is it more like driving on the wrong side of the road? To be continued.
Editor’s note: Dr. Shahar Madjar is a urologist at Aspirus and the author of “Is Life Too Long? Essays about Life, Death and Other Trivial Matters.” Contact him at [email protected]