Humans have always relied on ketones for energy when glucose sources were scarce (i.e. no fruits available during winter). It is a normal state of metabolism. In fact, most babies are born in a state of ketosis. However, with abundant sources of carbohydrate, people rarely access ketosis and it becomes a dormant metabolic pathway.Our ancestors likely had frequent periods of time when high carbohydrate food wasn’t immediately available. For this reason, our bodies are amazing at adapting to burning of ketones for fuel.
"I recommend only 5 percent of calories coming from carbs, which usually averages out to less than 30 grams," he says. "I understand why people get nervous and panic, thinking 'Can I even eat a salad?' This is why I recommend tracking only 'net carbs', which are total carbs minus fiber. For example, an avocado has 12 grams of carbs but 10 grams of fiber, which means it has 2 grams of net carbs. Also, green leafy vegetables are very nutritious and contain a lot of fiber, so you can almost eat them as much as you want and stay below your limit.
If you’re looking to get a jump start on your health and fitness goals this year, you may be thinking about trying the ketogenic diet. Maybe you’ve heard the phrase before — it’s a huge diet buzzword — but aren’t sure what it means. Here’s a primer: The ketogenic diet is an eating plan that drives your body into ketosis, a state where the body uses fat as a primary fuel source (instead of carbohydrates), says Stacey Mattinson, RDN, who is based in Austin, Texas.