The internet is filled with stories of how everyone from movie stars to ordinary people have shed stubborn pounds with the ketogenic diet. The ketogenic or “keto” diet has gained popularity in the last several years because of many possible benefits, including weight loss, increased energy, and relief from chronic illness. However, the diet is …
The internet is filled with stories of how everyone from movie stars to ordinary people have shed stubborn pounds with the ketogenic diet. The ketogenic or “keto” diet has gained popularity in the last several years because of many possible benefits, including weight loss, increased energy, and relief from chronic illness. However, the diet is extremely strict and difficult to maintain, and poses numerous risks. In this post, we cover everything related to the keto diet, including what it is, how it works, what to eat, the benefits of a keto diet, the risks of a keto diet, and what science tell us.
The ketogenic diet is a high fat, moderate protein, low carbohydrate eating pattern that helps your body burn fat for energy. This method of eating has been used for weight loss or diabetes prevention, treatment, and management since the 19th century.
The ketogenic diet differs from general healthful eating recommendations, as it requires restriction of many nutrient-rich foods that are sources of carbohydrates, including fruits, vegetables, whole grains, milk, and yogurt.
On a keto diet, carbs from all sources are severely restricted. With the goal of keeping carbs below 50 grams per day, keto dieters often consume no breads, grains, or cereals. And even fruits and vegetables are limited because they too contain carbs. For most people, the keto diet requires making big shifts in how they usually eat.
Instead of relying on the sugar (glucose) that is metabolized from carbohydrates (such as grains, legumes, vegetables, and fruits), the keto diet relies on ketone bodies, a type of fuel that the liver produces from stored fat. This reduction in carbs puts your body into a metabolic state called ketosis. When this happens, your body becomes incredibly efficient at burning fat for energy.
Without enough carbs for energy, the body begins breaking down fat into ketones, and they become the primary source of fuel for the body. Ketones provide energy for the heart, kidneys, and muscles. The body also uses ketones as an alternative energy source for the brain.
Although there is some variation in the amount of carbs permitted per day, a keto diet involves limiting carb consumption to around 20 to 50 grams. For context, 20 grams of carbohydrates is roughly a single potato, a half cup of cooked pasta, or half a bun.
The keto diet also has an extremely high fat requirement. For example, in a daily 2,000-calorie diet, that might look like 165 grams of fat, 40 grams of carbs, and 75 grams of protein. Some examples of fats are meat, fish, eggs, nuts, and healthy oils. Saturated fats from oils (palm, coconut), lard, butter, and cocoa butter are encouraged in high amounts, but some healthy unsaturated fats are also allowed on the keto diet—like nuts (almonds, walnuts), seeds, avocados, tofu, and olive oil.
With carbohydrate restriction, the keto diet rules out most fruits. However, there are certain fruits you can still eat. Generally speaking, they will be low-carb and low-sugar options. Here are a few examples:
Some fruits to avoid are high-sugar fruits such as bananas, grapes, pineapple, mango, and apples.
Vegetables are restricted to leafy greens (such as kale, Swiss chard, spinach), cauliflower, broccoli, Brussels sprouts, asparagus, bell peppers, onions, garlic, mushrooms, cucumber, celery, and summer squashes. It’s important to avoid white and sweet potatoes, as well as peas and corn, because of their high carb content..
Most animal proteins—such as eggs, beef, pork, poultry, and seafood—are low in carbs and thus appropriate for the keto diet.
Research shows that being in a state of nutritional ketosis notably leads to significant improvement in blood glucose control and weight loss. Other common benefits include reduced dependence on diabetes medication, , lower blood pressure, and improvements in insulin sensitivity and cholesterol levels.
Weight loss
Restricting carbohydrates enough to be in a state of ketosis leads to a significant reduction in body fat, as a high-fat, moderate-protein, and very-low-carb diet causes the body to burn body fat and dietary fat for energy. A diet high in carbs can induce bloating, weight gain, and poor health. But once your body is acclimated to ketosis, you can experience increased energy and a higher tolerance for physical activity.
Furthemore, since ketogenic diets consist of high amounts of fat–which are more satiating–they may reduce hunger-stimulating hormones. Without the sugar peaks and crashes, cravings disappear, and you feel satisfied for longer periods of time.
In a 2013 meta-analysis of 13 randomized controlled trials, researchers found that people following ketogenic diets lost 2 pounds more than those following low-fat diets over one year.
Similarly, another meta-analysis of 11 studies demonstrated that people following a ketogenic diet lost 5 pounds more than those following low-fat diets after 6 months.
Blood glucose control
Carbohydrate is the macronutrient that raises blood sugar the most. Because ketogenic diets are very low in carbohydrates, they eliminate the larger rises in blood sugar, which can help people with type 2 diabetes.
Although the keto diet may result in weight loss and lower blood sugars, it is extremely restrictive, which leads to short-term and long-term risks.
Short-term health risks include flu-like symptoms such as an upset stomach, headache, fatigue, and dizzy spells. This “keto flu” is often experienced by those who are new to the diet, as their body adapts to ketosis. Some people also report trouble sleeping.
Furthermore, cutting back on high-fiber vegetables, fruits, and whole grains also can increase the risk of constipation.
Long-term health risks of the keto diet include kidney stones, liver disease, and deficiencies of vitamins and minerals. To limit carbs, many nutrient-rich vegetables and fruits are cut out. Thus, intakes of vitamins A, C, K, and folate usually are low.
First, with so much fat to metabolize, the diet could lead to liver complications or make an existing liver condition worse. Second, the kidneys help metabolize protein, and the keto diet may overload them, leading to kidney stones. Lastly, the brain works best when the energy source is sugar metabolized from healthy carbohydrates, so low-carb diets may cause confusion and irritability.
The high-fat nature of the keto diet is very controversial. A considerable body of research has further shown that diets high in saturated fat may increase the risk for heart disease and other chronic health problems.
This eating pattern is not recommended for individuals with:
The keto diet has been used to manage epilepsy, a disorder characterized by seizures, for more than 100 years. More recent studies are evaluating the keto diet as an alternative treatment for obesity and diabetes. However, research findings on the benefits of the keto diet for these health conditions are extremely limited: Studies on the effectiveness of the keto diet were conducted with small groups of people, and most of the research about Alzheimer’s disease relies on research done on lab animals. In addition, there are also limited studies on the long-term health effects of the keto diet. In order to fully assess the safety of this eating pattern, more research is needed.
Body mass index and individual metabolic rates impact how quickly different individuals produce ketones. This means that on the keto diet, some people lose weight more slowly than others—even if they are following the same keto diet plan. For this group of people, the keto diet can be frustrating and may impact their motivation to make healthy dietary changes. Many people are not able to stick with the keto diet, and they gain back the weight lost when they return to their previous pattern of eating.
The keto diet comes with many benefits, but many doctors wouldn’t recommend the keto diet to their patients because it is ultimately not realistic or sustainable. Furthermore, The diet restricts fresh fruits and vegetables, whole grains, and low-fat dairy that can help with long-term weight loss and overall health. Moreover, eating a restrictive diet, no matter what the plan, is difficult to sustain, and once you resume a more typical diet, the weight will likely return.
Before dieting, do your research, consult a dietitian, discuss with your doctor, and make sure you’re being safe.
