The keto diet — eat all the fat you want, minus the carbs — seems like a miracle diet for those who are looking to lose weight fast while still enjoying their favorite foods. For obese individuals, it may be the golden ticket. Repeated studies have shown that following a keto diet can significantly reduce body weight, triglycerides, LDL cholesterol and blood glucose levels.
The ketogenic (or keto) diet was initially designed to treat severe epilepsy in infants and children. As an intervention diet, it was intended to be administered for short periods of time under the supervision of a medical team. Now popular for it’s rapid weight-loss side effects, the diet has moved to the mainstream public as an alternative low-carb diet.
In order to reach true ketosis, you need to switch to a different metabolic state where you use body fat as a fuel source instead of glucose. Running out of glucose means nutritionally starving as far as your body is concerned, and ketosis is the response. While using excess adipose tissue is generally seen as a good thing, it doesn’t happen in a vacuum. In addition to breaking down fat cells, your body also breaks down muscle in the form of protein to create glucose. As a long-term side effect, this means that the keto diet eventually decreases lean body mass, which can make it harder to lose weight once the diet has ended.
Getting 80-90% of your calories from fat, which is what’s generally required for true ketosis, is fairly difficult. Keto is not just low-carb, it’s also moderately-low protein. That requires filling your plate with avocado, coconut oil, fatty meats, gravy — and very few carbohydrates. While the range for carbohydrate intake vary from person to person, 25-30g is usually the maximum amount allowed to stay in ketosis. That’s the equivalent of one medium apple.
Without going into true ketosis, using ketone bodies instead of glucose for fuel, individuals risk taking in lots of saturated fat without the fat-burning effects of ketosis. Eating lots of butter and animal fat without being in ketosis will have the opposite effect: raising LDL, triglyceride and cholesterol levels instead of decreasing them.
Bone, Kidney and Microbiome Concerns
Circulating ketone bodies make the blood too acidic, which will draw calcium from the bones as a buffer response. While there are relatively few studies on long-term (more than 6 months) effects of a non-therapeutic keto diet, studies of children on the diet show high calcium levels in the blood, increased bone demineralization and increased risk of kidney stones.
Thanks to a very-low carb eating plan, the keto diet is effective when it comes to quick weight loss and stabilizing blood sugar levels. However, carbs are not just pasta and bread, they are beans, legumes, fruits, vegetables and whole grains. These foods contribute vitamins, minerals, antioxidants and fiber to the diet that’s hard to get without them. If you’re planning on trying out the keto diet, focusing on plant-based fats like nuts, seeds, avocados, coconut and olive oil will help to get some of the micronutrient losses back in.
Long-term, without the fiber from whole grains, vegetables and beans, you’re more likely to experience GI issues, like constipation and bloating. Additionally, you need fiber to maintain a healthy gut microbiome, essential for immunity and reducing inflammation.
While the ability to lose weight quickly can certainly seem appealing, it’s important to talk to your doctor and take the long-term risks into account before starting any diet.