What are Ketogenic Diets?
Many of my patients have been asking about a ketogenic diet. Is it safe? Would I recommend it? Despite the recent hype, a ketogenic diet is not something new. Russel Wilder first coined the phrase the “ketogenic diet” to treat epilepsy in 1921. For almost a decade, it enjoyed a place in the medical world as a therapeutic diet for pediatric epilepsy and was widely used until its popularity ceased with the introduction of anti epileptic agents.
In the 1970s, Dr. Atkins popularized his very-low-carbohydrate diet for weight loss that began with a strict two-week ketogenic phase. Over the years, other fad diets have incorporated a similar approach for weight loss. In the world of weight-loss diets, low-carbohydrate, high-protein eating plans often grab attention. The Paleo, South Beach, and Atkins diets fit into this category. They are all sometimes referred to as ketogenic or “keto” diets.
How do the diets work?
The keto diet aims to force your body into using a different type of fuel. Instead of relying on sugar (glucose) that comes 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 when the body is in starvation mode.
Burning fat seems like an ideal way to lose pounds. But getting the liver to make ketone bodies is tricky:
- It requires that you deprive yourself of carbohydrates, fewer than 20 to 50 grams of carbs per day (keep in mind that a medium-sized banana has about 27 grams of carbs!).
- It typically takes a few days to reach a state of ketosis.
- Eating too much protein can interfere with ketosis.
What do you eat?
Carbohydrates normally account for at least 50% of the typical American diet. In the keto diet you’re limited to only 5-10%. Specifically, in a 2,000 Kcal per day diet, you’d only be allowed up to 20 to 50 grams per day. A ketogenic diet primarily consists of high-fats, moderate-proteins, and very-low-carbohydrates. The rest of the dietary macronutrients are divided into approximately 55% to 60% fat and 30% to 35% protein.
Because the keto diet has such a high fat requirement, followers must eat fat at each meal. In a daily 2,000-calorie diet, that might look like 165 grams of fat, 40 grams of carbs, and 75 grams of protein. However, the exact ratio depends on your particular needs.
Some healthy unsaturated fats are allowed on the keto diet — like nuts (almonds, walnuts), seeds, avocados, tofu, and olive oil. Saturated fats from oils (palm, coconut), lard, butter, and cocoa butter are encouraged in high amounts.
Protein is part of the keto diet, but it doesn’t typically discriminate between lean protein foods and protein sources high in saturated fat such as beef, pork, and bacon.
What about fruits and vegetables? All fruits are rich in carbs, but you can have certain fruits (usually berries) in small portions. Vegetables (also rich in carbs) 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.
There are multiple risks to a keto diet.
Hard to metabolize: Meat is harder to break down in the digestive system than plants are. Eating a diet that is high in meats and natural fat may be taxing on the digestive system. Eating high fat meals all the time overloads the digestive system with hard to digest food, instead of plant-based sources. Plants such as fruits and vegetables also act as natural detoxification agents to eliminate toxins from the body.
Nutrient deficiency: If you’re not eating a wide variety of vegetables, fruits, and grains, you may be at risk for deficiencies in micronutrients, including selenium, magnesium, phosphorus, and vitamins B and C.
Liver problems: With so much fat to metabolize, the diet can cause or exacerbate any existing underlying liver conditions.
Kidney problems: The kidneys help metabolize protein, and the keto diet may overload them by recommending a third more than what’s encouraged. (The current recommended intake for protein averages 46 grams per day for women, and 56 grams for men).
Constipation: The keto diet is low in fibrous foods like grains and legumes so abdominal bloating and gas is common.
Fuzzy thinking and mood swings: The brain needs sugar from healthy carbohydrates to function. Low-carb diets may cause confusion and irritability. Eating high fat meals all the time can also make a person tired because plants such as fruits and vegetables provide natural energy.
Osteoporosis: A condition that is characterized by loss of the normal density of bone, resulting in brittle bones, which are subject to fracture. The disease process can be silent (without symptoms) for decades. There is a potential increased risk of osteoporosis with a low-carb diet where calcium loss can result if protein intake remains high and calcium intake remains low. The ratio of animal to vegetable protein intake may also contribute to bone loss.
Increase gouty attacks: For now, it’s best to stick with conventional wisdom regarding food and gout — that most diets high in animal proteins are risky for a person with gout. We know that red meats and seafood are especially rich sources of purines, and when eaten in excess, can raise uric acid levels. When people with gout ate a diet high in purines from animal sources over a two-day period, they were nearly five times more likely to have a gout flare compared with people who avoided purines, in a study from Boston University published in the journal Annals of The Rheumatic Diseases. “A poor diet can absolutely lead to more gout exacerbations, even if the uric acid is fairly controlled with medication,” says rheumatologist Randall N. Beyl Jr, MD.
Increased risk of heart disease: Research shows there is an association between eating a diet high in animal products and heart disease. Many animal products are high in saturated fats that are high in cholesterol, which can clog arteries and impact blood flow to the heart. Blood delivers important nutrients and oxygen needed to maintain proper cardiovascular system health. The ketogenic diet is both high in saturated animal fats and low in protective antioxidants from plant sources, as antioxidants protect organs such as the heart, further increasing an individual’s risk of developing this disease. It’s recommended that saturated fats be limited to no more than 7% of your daily calories because of the link to heart disease. The keto diet is associated with an increase in “bad” LDL cholesterol, which is also linked to heart disease. I have seen significant changes in lipid control on these diets, often elevating lab values to dangerous levels that can cause significant harm in the long run.
Diabetes: Fiber is only found in plant sources of food and is limited while on the ketogenic diet. Fiber controls blood sugar levels by limiting the amount of glucose that is dumped into the bloodstream. Because of this, fiber reduces blood sugar spikes and can help control diabetes. Eating a diet that is high in vegetables is the best way to incorporate fiber into one’s diet. This would be hard to accomplish on a diet that limits its overall carbohydrate intake to just two to four percent. Or as previously stated- the equivalent of a small banana.
Skin issues: Research indicates a link between eating meat and acne. The ketogenic diet is high in meat and low in vegetables, which have healing powers for the skin. Vitamins A, C, and E can help prevent the appearance of skin wrinkles. They can also protect the skin against the sun’s damaging UV rays. Vitamin C is necessary for collagen production, which helps restore new, healthy skin. These vitamins are only found in plant sources such as fruits and vegetables. A person with a diet that is high in meats and low in fruits and vegetables may experience more skin problems than a person who follows a plant-based diet.
Interact with medications: For example, there is some evidence the ketogenic can pose dangers for anyone with high blood pressure. Blood pressure medications and this diet method can react adversely to one another due to a sudden drop in blood pressure in the first few weeks. Considering the ketogenic diet can be harmful to those with high blood pressure, consulting a medical professional is a critical step in avoiding or minimizing any concerns.
It’s expensive: If you and your family are on a tight budget, properly following and thriving on the ketogenic diet can be difficult. For one, with the rising cost of food, especially meats, and animal-based products, this diet can get expensive quick as a majority of your protein and fat sources come from animal-based proteins and fats. And many of the ketone supplements can get incredibly expensive as well, especially if there are more than two individuals in a household following the diet, as you will need to buy supplements more often. Unless you plan to start buying in bulk or purchasing meats and organic foods when they are on sale and freezing them, expect to see your grocery bill increase significantly on the ketogenic diet.
These risks add up- so make sure you talk to provider before ever attempting a ketogenic diet.
What about the other diets?
The popular low-carb diets (such as Atkins or Paleo) modify a true keto diet. But they come with the same risks if you overdo it on fats and proteins and lay off the carbs. So why do people follow the diets? They’re everywhere, and people hear anecdotally that they work, so they want to try them too. It also sounds like a quick fix to a long term issue. While in the short term the ketogenic diet may help one lose weight, this is not sustained over the long run. In addition, countless studies show that the diet is associated with many complications that often lead to emergency room visits and admissions for dehydration, electrolyte disturbances, and hypoglycemia (low blood sugar level.)
We just don’t have enough data to assess or understand the possible long term impact following these diets may create. We do know eating a restrictive diet, no matter what the plan, is difficult if not impossible to sustain. Once you resume a normal diet, the weight will likely return.