If you haven’t seen it thrown around Reddit, you might have heard it ballyhooed by a gym bro: ketosis just works, bro! You get to eat all the bacon and cream you can stomach, shred fat, maintain muscle, and still dominate your sport.
The very, very high-fat ketogenic diet is one of the hottest trends in nutrition, but while there are some success stories in endurance athletes, there’s very little evidence in strength sports. It may be delicious, but is it a smart pick for your next meet?
What Are We Talking About, Exactly?
Your body kicks into ketosis when carbohydrate intake is so low that the body doesn’t want to use it as a fuel source. Typically, that happens when fat makes up 60 to 70 percent of overall calories, protein 20 to 30 percent, and carbs are under 50 grams per day. It usually takes less than a day for your body to start producing ketones for fuel — a sure sign is when when your breath starts to smell of acetone, a ketosis by-product. (Incidentally, it kind of stinks. Like a mixture of fruit and nail polish remover, in which acetone is a key ingredient.)
“If you look at one of the main fuels the body can burn, carbohydrates and fat are the main two, and a layer down are the sort of ‘subfuels,’ lactate and ketones,” says Dr. Mike T. Nelson, CSCS, an adjunct professor at the Carrick Institute whose PhD focused on metabolic flexibility.
“Historically, ketones have not shown up in the body in enough quantities for the body to use unless you’re in starvation,” he explains. “But you can get there via what’s called a ketogenic diet. When you do that, your body will start producing ketones, which can then be used for fuel. Then you’re in a state of ketosis.”
Though first suggested as a therapeutic tool by the Mayo Clinic in the 1920s, it wasn’t until the late 20th century that ketosis gained popularity as a tool to treat epilepsy and other brain disorders. Some research has shown that more than half of children with epilepsy who go on the diet experience at least fifty percent fewer seizures.
That’s always been its main use: therapeutic. There’s also some shakier evidence that it can help the body to fight cancerous tumors and prevent diabetes.