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As trendy as it is, the Keto diet is nothing new. It’s been used in clinical settings for years to treat some medical conditions, and low-carb diets in general have been around since the early 1970s and the Atkins Diet. But does Keto really work? And, more important: is it healthy? It definitely can be, with a few simple fixes.
What It Is
The Keto diet—short for “ketogenic”—is an ultra-low-carb regimen designed to shift the body into what’s called a state of ketosis. Most of the body’s cells use blood sugar (derived from dietary carbs) as their main source of energy. If carbs are restricted and sugar’s not available, the body starts breaking down stored fat into chemicals called ketones—that’s ketosis. It usually takes two to four days of eating fewer than 50 grams of carbs a day for the body to shift. The intended result: more balanced blood sugar and rapid weight loss. Other research also suggests that the Keto diet may influence appetite-control, and ketones themselves are thought to suppress appetite.
Individual interpretations of the diet vary, but most restrict carbs to less than 50 grams a day, and some to 20 grams. Unlike the Atkins Diet, which gradually increases carbs, the Keto diet keeps carbs low to encourage the body to remain in a state of ketosis. Protein intake ranges from 20–30 percent of calories per day, while fat accounts for 60–75 percent.
Properly designed, the Keto diet is considered safe in the short run, though side effects are typical. The most common: nausea, vomiting, headache, fatigue, dizziness, insomnia, and constipation—a collection of symptoms known as “keto flu.” Few long-term studies have examined the diet’s safety, but it can be harmful for people with kidney disease, pancreatitis, and other conditions, as well as for diabetics taking insulin. If you fall into any of these categories, check with your doctor first.
Related: The Ultimate Keto Guide
What the Research Shows
While the Keto diet is geared for weight loss, some research suggests that it may also prevent seizures and protect against cardiovascular disease, metabolic syndrome, and some neurological disorders. Here’s what the science shows:
Weight loss. Dozens of studies show that people who follow a Keto or very-low-carb diet lose weight faster than those on a more traditional diet. Keto diets also appear to be more effective than low-fat diets for weight loss, and can result in substantially more fat loss. One meta-analysis comparing long-term (more than one year) effects found that low-carb diets in general led to significantly greater weight loss than low-fat regimens, while also preserving basal metabolic rate (BMR)—the number of calories required to keep your body functioning at rest. By contrast, BMR dropped by more than 400 calories a day in people following a low-fat diet.
Blood sugar and diabetes. It’s clear that a high intake of sugar is linked with increased risk of diabetes, and by some estimates, a sugar-rich diet increases diabetes risk by as much as 26 percent. By mostly eliminating sugar, the Keto diet can improve blood sugar control for patients with type 2 diabetes, and very-low-carb diets appear to be significantly more effective than low-fat diets for diabetes prevention and control.
Cardiovascular disease. Several studies suggest that following a Keto diet reduces triglycerides and harmful LDL cholesterol levels, while increasing beneficial HDL cholesterol levels. In other studies, a very-low-carb diet was more effective at reducing cholesterol and other cardiovascular risk factors than a low-fat diet.
How to Make It Healthier
The main criticisms of the Keto diet: it’s restrictive, unbalanced, and hard to follow, and it generally shouldn’t be a life-long eating plan. It also limits fiber- and antioxidant-rich fruits, vegetables, and legumes—shown to protect against cancer, Alzheimer’s, and other diseases.
The Keto diet itself also doesn’t distinguish between low-quality fats from processed foods and mono-unsaturated plant-based fats (or clean saturated fats like coconut oil). To turn your Keto diet into the healthiest possible version, start with these basics:
- Stick to whole, unprocessed foods, and save packaged Keto products for an occasional treat.
- For protein, minimize processed meats such as bacon and sausage, and focus on grass-fed or pastured poultry, lean beef, and eggs. Include fatty fish such as wild salmon, sardines, herring, and tuna for omega-3 fats.
- Skip processed cheeses and varieties with additives or colors. Keep an eye on the sodium content and choose low-carb, organic versions made from grass-fed cows’ milk. Include full-fat yogurt for probiotics, but avoid those with artificial flavors, colors, or sweeteners—add your own natural sugar alternative.
- For cooking, emphasize monounsaturated fats and plant-based saturated fats. Olive oil, coconut oil, and avocado oil are the best choices. Supplement fats with avocado, olives, nuts, seeds, and nut butters within your daily carb count.
- Fruits are limited, but allowed, on the Keto diet. Focus on fiber- and antioxidant-rich choices such as blackberries, raspberries, and strawberries, with small amounts of other lower-carb selections such as clementines, plums, and cantaloupe.
- Make vegetables count by eating the most nutrient-dense, low-carb varieties. Spinach, lettuce, kale, asparagus, cabbage, cauliflower, green beans, broccoli, Brussels sprouts, green peppers, avocado, tomatoes, and olives are excellent options. Some root vegetables, including carrots, rutabagas, and beets can be added in moderation.
- Avoid artificial sweeteners and excessive sugar alcohols. Stick to monk fruit, erythritol, and stevia.
- Consider the “Keto 2.0” plan—a modified version of the typical Keto diet that focuses on plant-based fats, with less meat and more fish for protein.
- Take a high-quality daily vitamin to fill in nutrients often missing on a Keto diet. A digestive enzyme can help with nausea and bloating during the transition, and electrolyte supplements can make up for lower levels of potassium and magnesium.
Related: 5 Ways to Succeed on the Keto Diet