You've probably heard of something called the ketogenic, or keto, diet — but what exactly is it? "Keto" refers to ketogenesis, a process in the body that results from significantly reducing the carbohydrates in your diet and increasing your fat intake. The keto diet has been around a long time and has even been used for medical reasons, but athletes, celebrities and others are turning to the regimen as an effective weight loss technique.
How Does It Work?
When you're on the ketogenic diet, you are in a state similar to fasting – your body is using fat for fuel. Normally your body gets energy from readily available carbohydrates, but on a keto diet, your carb intake is slashed. "When carbs are available, the body will naturally turn to them for energy instead of using dietary fat or stored body fat," explains Pam Nisevich Bede, RD, MS, a dietitian with Abbott.
However, without regular replenishing of carbohydrates, the body begins to break down fat for energy, resulting in the formation of ketones. Ketones can eventually be used by the body for energy.
The move from carb to fat fueling is marked by an adaptation phase. This phase can come with some lethargy and other symptoms as your body adjusts (we discuss this more later) but you'll start to notice weight loss as well as more steady energy and less hunger. "This can be a hard shift for someone who's been fueling with bagels and pasta their entire life, but after three to five weeks, the body adapts," Bede explains.
What You'll Be Eating
The key to keto is knowing what's in your food. "On a standard diet, most people consume approximately 50-55 percent carbohydrates, 20-25 percent protein and 20-25 percent fat," says Bede. "With a keto diet, the breakdown is approximately 75 percent fat, 20 percent protein and 5 percent carbohydrates." For example, a woman who weighs 150 pounds and is moderately active is recommended to eat 25 grams of carbs (think one medium sized apple!), 86 grams of protein (a little over three 3 oz chicken breasts) and 189 grams of fat (hello, avocados and nuts!) per day on the keto diet.
Interested in a keto meal plan? Check out a full day of recipes here.
A typical keto diet will consist of foods high in protein and healthy fats, including red meat and poultry, fatty fish, non-starchy vegetables, dark, leafy greens, avocado, coconut oil, keto-style coffee, bone broths and of course plenty of water. When you're in a pinch, you can grab a keto-friendly protein shake to meet your targets to stay fueled and satiated on the go.
What to Expect
During the transition to a keto diet, you might experience some minor side effects. Don't get discouraged — it's a normal part of the process. Bede explains that new diet adopters might feel symptoms of "keto flu," including headaches, nausea, fogginess, muscle cramping and fatigue. Make sure you are not too low on electrolytes — sip on broth or take a salt tablet to get needed sodium. If you're an avid runner or athlete, you might feel a bit drained at first during those workouts, but Bede notes that "Once adapted, gym goers and strength athletes will have no issues cranking through a workout session."
Remember that this transition might last about three to five weeks, and the benefits can certainly outweigh the immediate side effects. Bede notes that you might notice increased energy throughout the day and some people report a feeling of greater mental clarity or focus. Further, the combination of fat and protein on the keto diet may contribute to increased feelings of satiety.
A keto diet is an option for people looking to lose fat and build muscle, but like any diet, it's not the best choice for everyone. Pregnant women, serious endurance athletes and people managing Type 1 diabetes as well as other conditions may have trouble with the restrictions of a keto diet. If you are considering starting a keto regimen, research it well, consult with your doctor and have regular blood lipid testing to ensure your cholesterol and other levels stay in healthy ranges.