What’s a ketogenic diet?

Have you been hearing the term “ketogenic diet” thrown around on the internet lately and wondered exactly what it was? Here’s a quick look at the ketogenic diet and weight loss; as always, discuss weight control plans with your doctor and/or a Registered Dietitian before striking out on your own.

Zucchini Pasta Salad with Parmesan
Zucchini Pasta Salad with Parmesan / Dietplan-101.com / CC BY 2.0

Facts about ketosis

Ketosis is achieved when one severely restricts carbohydrates and relies instead on mostly fat (and some protein). What’s happening is that the body isn’t getting glucose, (a sugar derived from carbohydrates) for energy, so it starts breaking down body fat for energy. When fat stores become your major source of energy, the liver produces ketones (also called “ketone bodies”) which are byproducts that build up in the blood to measurable levels during the metabolic state called ketosis. Ketones can be detected in urine, using testing kits that marketed to people with diabetes. Mild ketosis occurs naturally in humans during fasting, and after vigorous exercise for example.

The state of ketosis recommended by some for quick weight loss, however, is really another form of a fad diet. When your body is running on ketones instead of glucose, there are several noticeable effects: decreased hunger (after an initial period of adjustment) which dieters may view as helpful, headache, nausea and bad breath (sometimes called “acetone breath” because acetone is one of the ketones that our bodies make and it makes itself known through the breath). Interestingly, the brain typically uses glucose for fuel, but it can also use ketones if necessary. Some people report feeling “foggy” during ketosis, and there is an indication that memory problems may also occur.

Losing weight on a ketogenic diet

There is some evidence that low-carbohydrate diets can improve some measures of heart health, such as HDL cholesterol and triglyceride values, but it’s likely that weight loss is the goal most people are seeking when they attempt a ketogenic diet. Low-carb diets do seem to lead to greater short-term weight loss than more moderate-carb diets or low-fat diets (several studies have shown this). Experts sometimes argue that this may be just because of lower caloric consumption, which does make sense due to the appetite suppression induced by ketosis.

In the long term, the weight loss differences between these different approaches become quite small. Maybe this is because it’s not easy to stick to a super low-carb diet and as time goes by, people “cheat” more. Or maybe there are other reasons; there isn’t a lot of research about the health effects of a ketogenic diet followed long-term (for years).

Is ketosis ok?

There are medical uses for a ketogenic diet. In children with epilepsy it seems to reduce seizures, and increasingly there is interest in expanding that therapy to adults. There is even research into the use of a ketogenic diet for Alzheimer’s disease and cancer and other neurological issues. For weight loss, one might consider a ketogenic diet a stricter version of a “paleo diet.” People with Type 1 diabetes can fall victim to ketoacidosis, which is typically caused by a deficiency of insulin, which is different from the dietary or nutritional ketosis discussed in this post. Nevertheless, high amounts of ketones in the urine is a sign of ketoacidosis and requires a physician’s attention.

Is occasional ketosis unsafe for you? You should discuss this with your doctor. Will any immediate harm befall you if you go a day or two without carbohydrates? Not likely. That, however, is not the same as chronic ketosis, for which little documented safety information exists.