October 10, 2019
By Anthony Auriemma, MD, JD
The best ketogenic diet for morbid obesity is a dietary plan that you can live with long-term. A short-term dietary change is not effective for long-term weight loss. Once we return to previous patterns of eating, we almost universally see weight regain. Any dietary intervention that does not result in lifelong change in eating patterns is destined to fail. Therefore, the best ketogenic diet is one that you enjoy, does not leave you feeling deprived, and is reasonable to maintain for the long haul.
A ketogenic diet is nothing new. It has been recorded as far back as 400 BC when Ancient Greeks found that fasting was helpful for treating epilepsy. Over the past two centuries, the ketogenic diet has had many different names: the Banting Diet (1860s), the Drinking Man’s Diet (1962), and the Atkin’s Diet (1972). All of these diet plans reduce carbohydrate levels low enough that the body must break down fat instead of carbohydrates for the primary source of energy.
Effects of Ketogenic Diets
A ketogenic diet causes a rise in circulating ketones throughout the blood stream. An elevation of ketones in the blood stream is called ketosis. Ketosis is not the same as a dangerous condition in individuals with diabetes called ketoacidosis. Ketosis is a safe and natural way for the body to break down fat during periods of famine or with a lack of carbohydrates.
Ketones are small energy molecules derived from the breakdown of fat. Ketones can be measured by urine dipsticks, blood tests, and breath tests. Ketones in the blood stream often cause a characteristic “fruity” breath odor.
Ketogenic diets are currently popular for weight loss, but there are other potential benefits. There is good evidence that ketogenic diets help with weight loss, epilepsy, type 2 diabetes, and improvement in cardiometabolic risk factors. There is emerging evidence that ketogenic diets may be helpful for acne, polycystic ovarian syndrome, certain brain cancers, and brain diseases like Alzheimer’s.
Four Types of Ketogenic Diets
Ketogenic diets can be broken down into four different categories: the “classic” ketogenic diet, medium chain triglyceride diet, modified Atkin's diet, and a low glycemic index diet. The benefit of alternative diets to the classic ketogenic diet is the ability to increase protein and/or carbohydrate intake while still maintaining the weight loss benefits of ketosis.
- Classic Ketogenic Diet: The “classic” ketogenic caloric intake is typically made up of a ratio of 4:1 or 3:1 grams of fat to combined grams of carbohydrates and protein. A 4:1 ratio would break down caloric intake to 90% from fat, 6% from protein, and 4% from carbohydrates. The difficulty with a classic ketogenic diet is palatability. The high level of fat and low level of carbohydrates can interfere with the taste of food and non-nutritive sweeteners may help with palatability.
- Medium Chain Triglyceride Diet: This second type of ketogenic diet allows the individual to increase the amount of carbohydrates and protein in the diet. An increase in carbohydrates and protein makes the diet more palatable. However, in order to keep ketone levels elevated, fat intake should come from medium chain triglycerides. Medium chain triglycerides help with ketosis because they are more easily absorbed and converted to ketones than long chain triglycerides. High levels of medium chain triglycerides can be found in coconut oil and palm kernel oil.
- Modified Atkin's Diet: The modified Atkin's diet is different than a typical Atkin's diet because it replaces some of the protein in an Atkin's diet with fat. The typical ratio of fat to protein and carbohydrates is 1:1. The modified Atkin's diet is often used as a stepping stone to or from a “classic” ketogenic diet, but many individuals have successful long-term weight loss with a modified Atkin's diet.
- Low Glycemic Index Ketogenic Diet: The glycemic index measures the effect that different types of carbohydrate foods have on blood sugar. Simple carbohydrates like sugar are rapidly absorbed and therefore have a high glycemic index. Complex carbohydrates like whole grains are more slowly absorbed and therefore have a lower glycemic index. By focusing on intake of low glycemic index foods, individuals on a low glycemic index ketogenic diet can consume more carbohydrates than in the “classic” ketogenic diet while still maintaining ketosis.
Choosing the Best Ketogenic Diet
Whichever type of ketogenic diet you choose to follow, most individuals will have to become comfortable eating more fat than their baseline diet. Fat has been vilified since the late 1970s, and the medical community is not in total agreement about the effects of increasing fat intake. There are a number of large studies over the past 40 years that show no detrimental effects of fat intake on health. One area of relative agreement in the medical community is that replacing saturated fats (animal fats) with polyunsaturated and monounsaturated (plant fats) may be healthier for you.
The choice of which type of ketogenic diet to use for weight loss and obesity should be determined based on which dietary plan works best with your lifestyle. Due to the popularity of ketogenic diets, there are a number of food products and meal replacements available to help you maintain your dietary plan. Make sure to do your research, prepare your plan, and enjoy the benefits of a ketogenic diet!