While specialists recognize the effectiveness of the ketogenic diet — which restricts carbohydrate intake, in turn reducing the availability of glucose — in tackling certain medical conditions, they also warn against potential side effects such as nausea, fatigue and headaches.
By definition, a ketogenic diet is not a balanced diet. Around 75% of calories come from fats, although the pro-inflammatory omega 6 variety, such as sunflower oil, grape seed oil and wheat germ are usually avoided.
Followers of the diet can eat meat, poultry, fish, seafood, eggs, butter, oils, oilseeds, avocados, and certain vegetables with low carbohydrate levels — such as green leafy vegetables like spinach, kale and lettuce — as well as hard cheeses.
Other dairy products, such as milk and yogurt (full-fat varieties), are allowed in moderation. Vegetables with higher carbohydrate contents — such as carrots, beetroot, sweetcorn and sweet potato — are off the menu.
Since cells no longer have access to glucose converted from carbohydrates, the body has to find a new source of energy. In fact, it essentially adopts the same process as when fasting, relying on “ketone bodies” for energy. Ketone bodies are three types of molecules that result from the conversion of fat into fatty acids in the absence of glucose. Two ketone bodies are used by the heart and the brain as a source of energy and the third is eliminated by the body.
Beneficial for epilepsy
As well as its scientifically recognized benefits in cases of difficult-to-control epilepsy in children, the most evident benefit of the ketogenic diet is weight loss, which certain studies have found to be slightly greater than with high-protein diets.
The ketogenic diet is currently seeing renewed interest from medical researchers thanks to its potential therapeutic benefits in other neurological conditions, such Alzheimer’s, Parkinson’s, stroke-related brain injury and cancer.
Blood sugar levels can improve in diabetic followers. Plus, a 2013 study found that a ketogenic diet caused “bad cholesterol” (LDL) levels to rise while blood pressure, triglycerides and “good cholesterol” (HDL) all improved.
However, doctors warn of the diet’s side effects, which can include nausea, fatigue and headaches, in turn reducing appetite and food intake. Followers should also beware of deficiencies in fiber and vitamins.