The ketogenic diet is an ultra-low-carbohydrate, high-fat diet that has been used for decades to treat certain medical conditions. Today, adherents claim that it will help you drop pounds while boosting your energy levels and controlling your blood sugar. Its promise of fast and aggressive weight loss is a compelling one in our world of quick fixes, but the ketogenic diet can be complicated in its execution and the research of its long-term benefits and drawbacks is ongoing.
“Most people’s expectations are to lose weight with this diet. However, whether this is a sustainable strategy has yet to be determined. I advocate for whole health and taking care of all aspects of it, not just dropping weight,” says Colin Zhu, DO, a family physician who specializes in lifestyle medicine.
Here are five fast facts about the ketogenic diet—including its pros and cons.
- Burning fat: On most diets, the body uses glucose as its primary energy source. The ketogenic diet essentially forces the body to use fat as its main source of energy instead. It does this by mimicking a state of starvation where the body breaks down fat stores and converts them into ketones through a biochemical process called ketosis.
- Reaching ketosis: Generally speaking, the ketogenic diet is composed of 70-75 percent fat, 20-25 percent protein, and 5-10 percent carbohydrates. This strict formula is the key to ensuring a person enters the metabolic state of ketosis, which isn’t necessarily easy. In fact, reaching and maintaining ketosis can be exceptionally challenging for many people and requires diligence and planning. Newbies to the keto diet may experience symptoms such as dizziness, headaches, brain fog, nausea and irritability, says Dr. Zhu. This is sometimes referred to as “the keto flu.” These side effects generally go away after several weeks once someone becomes “keto-adapted.”
- Nuts and bolts: Foods to be limited on the ketogenic diet include: whole grains; beans and legumes; starchy vegetables like yams and potatoes; high-carbohydrate fruits like apples, oranges and bananas; alcohol; sugar; and low-fat dairy products. The keto diet does promote eating meat from various sources, as well as eggs, fish, avocados, coconut and olive oils and non-starchy vegetables.
- The good: Beyond weight loss, the ketogenic diet has been in use for conditions like epilepsy since the 1920s and obesity treatment since the 1960s.“ The keto diet really alters energy metabolism in the brain, so that’s why it’s thought to stabilize the functions of the neurons exposed to seizures in people with epilepsy,” says Junella Chin, DO, who uses the keto diet as a tool for treating children with intractable epilepsy in her integrative medical practice. “It helps children with seizures decrease their episodes and shorten their recovery time from seizures.” The keto diet has also been implicated for therapeutic use in chronic diseases such as heart disease, neurological conditions, polycystic ovary syndrome, and cancer. There’s also limited evidence that insulin sensitivity improves on the diet, which bodes well for managing diabetes.
- The bad: The downside of a ketogenic diet is that there is no well-established evidence to support its sustainability on a long-term basis, and further well-controlled trials are recommended, says Dr. Zhu. Recent research published by The Lancet found that restricting carbs and replacing them with animal-based protein and fat could lead to a shorter lifespan. For children with epilepsy, the biggest challenge of the keto diet is compliance, says Dr. Chin. “We struggle with compliance with kids and then parents because, of course, parents need to be on board too. And constipation can be a really big side effect that deters compliance.”
While studies of the ketogenic diet have shown short-term benefits for people that include weight loss and improvements in blood sugar and blood pressure, the jury is still out on whether these benefits can be sustained long-term.
“The ketogenic diet has the potential to be a game-changer,” says Dr. Zhu, “but a lot depends on whether its benefits pan out in large-scale trials and whether individuals can tolerate its dietary restrictions over the long haul. People struggling to lose weight for health reasons should keep it on their radar and stay tuned for more conclusive information.”