Is A Ketogenic Diet Right For You?
Matthew Brengman, MD, FACS - Weight Loss Surgeon


The ketogenic diet is a high-fat, low-carbohydrate diet that transitions the body’s fuel supply to burn fat instead of carbs.

For years, the properties of the diet have been successful in helping to control some seizure conditions, such as epilepsy. More recently, the ketogenic, sometimes called keto or low-carb, diet has gained popularity as a means of weight loss. As is true with most things in life, though, there are pros and cons to consider.


What is ketosis?

Metabolism is the process by which the body breaks down substances to use for energy. Ketosis is a type of metabolism that burns stored fats when the body does not have enough glucose, a type of sugar, to use for energy.

The ketogenic diet mimics the effects of fasting on the body. Glucose is the easiest source of energy for the body to use, and usually comes from the carbohydrates that we eat. Once glucose is burned off, the body uses fat as a source of energy. This use of fat creates a by-product called ketones.

Ketones are acidic and, in high amounts, can build up in the blood and urine resulting in a state of ketoacidosis. The chemistry of the blood is thrown off balance and may result in harmful effects on the heart, kidneys, and central nervous system.


What are the pros of a ketogenic diet?

In a recent study in the Journal of American Medical Association, some researchers found that “people on ketogenic diets tend to lose more weight and keep more of it off than people on low-fat diets. People placed on these diets often report decreased hunger,” according to Amy Miskimon Goss, PhD, RD, an assistant professor at the University of Alabama at Birmingham (UAB) Nutrition Obesity Research Center.

This may be especially important for some obese patients. If the ketogenic diet provides a more satisfying result than other diets, they will feel less hungry, have more energy, and may lose weight faster than on other plans. This, in turn, has a motivating effect. In addition to weight loss, some diabetes patients have found that the reduction of carbohydrates while on the ketogenic diet resulted in better control of their glucose levels.

Some researchers believe benefits of the ketogenic diet include:

  • Reduced blood glucose levels.
  • Better controlled seizures in children and some adults.
  • Higher weight loss, especially in obese individuals.
  • The elimination of many unhealthy, processed foods from the diet.
  • More stable metabolism, in contrast to a low-fat diet where metabolism can decrease significantly.

What are the cons of a ketogenic diet?

While the ketogenic diet sounds enticing, some physicians and dieticians urge caution. Critics of the diet say it is a short-term fix and that its high fat content can lead to other health problems. Other downsides may include:

  • It is a very strict diet plan. If a normal amount of carbs are consumed again, the body exits its state of ketosis, and weight gain will begin immediately.
  • It should not be used by anyone in any stage of kidney disease.
  • It should not be used when pregnant, nursing, or by anyone with gestational diabetes.
  • Using body fat for fuel puts your body in a fasting mode, somewhat like a state of starvation. Fasting is not a long-term weight-loss solution.
  • Increased cholesterol levels, potentially increasing risk of cardiovascular disease.
  • Increased risk for kidney stones due to acidic ketones.
  • Excessive excretion of calcium, raising the risk of osteoporosis.
  • May limit social opportunities due to extremely restrictive diet.

In a recent U.S. News & World Report ranking of best diets, the ketogenic diet did not fare well. An expert panel of top U.S. nutritionists, dietary consultants, and physicians, evaluated 40 different diets in 9 categories. According to Angela Haupt, assistant managing editor of health at U.S. News & World Report, the ketogenic diet is “the diet of the moment, but it can be a pretty extreme plan. There is a very strict carb limit. Our experts say it's not necessary to be so extreme or restrictive.” Furthermore, Haupt continued, “One expert said if a diet recommends snacking on bacon, you can't take it seriously as a health-promoting way to eat.”

The Mediterranean and DASH diets are better supported in promoting long-term healthy living and controlling against a wide range of diseases. In general, they are easier for most people to sustain over a lifetime.


What foods are and are not part of a ketogenic diet?

In many keto diets, 3 to 4 grams of fat are consumed for every 1 gram of carbohydrates and protein. This results in getting up to 80% of calories from fat. The range of food is somewhat limited, so some find it easier than others to maintain it. To get the most benefit, though, the diet must be followed as closely as possible. Generally, the ketogenic menu focuses on eating:

  • Protein (fish, meat, poultry) in moderate amounts
  • Eggs
  • Full-fat dairy
  • Full-fat condiments like mayonnaise, oil, or butter
  • Non-starchy vegetables
  • Limited servings of fruit
  • Fats & oils
  • Some nuts and seeds

In general, foods that are white in color are off-limit. This includes bread, potatoes, rice, pasta, and most baked goods. Most meat, fish, or poultry are fine on the diet, as are eggs, full fat cheese, green vegetables, and most butters and oils.


Are there any side effects of the ketogenic diet?

The fat-based ketogenic menu can have side effects that appear within a few days of starting the diet. These may include:

  • Constipation due to increased consumption of high-fiber foods.
  • Nausea and vomiting, sometimes called the Keto Flu.
  • Irritability.
  • Sleepiness.
  • Dehydration—make sure you have adequate fluid intake.
  • Vitamin deficiencies due to a restrictive diet.

Rare side effects can include:

  • Delayed growth due to nutritional deficiency.
  • Kidney stones.
  • Inflammation of the pancreas (pancreatitis).

The good news is that most side effects are short-term and should disappear as your body adjusts to the diet. Depending on your overall health and your long-term goals, your physician can help determine if a ketogenic diet is right for you.


Sources:
U.S. News & World Report
The Diabetes Council
“Interest in the Ketogenic Diet Grows for Weight Loss and Type 2 Diabetes.” JAMA, 2018