Ketogenic Diet

  • 5 Minutes Read
  • Nov 14, 2017

There are many structured eating plans available for weight loss. This post describes the Ketogenic Diet - what it is, the pros and cons, and whether or not it is effective for weight loss.

Ketogenic Diet

What is the Ketogenic Diet?

The ketogenic diet is a rather recent entry on the weight loss scene, but it has been around for much longer. Hundreds of years ago, people recognized that fasting helped control seizures, such as from epilepsy. But fasting isn't a realistic long-term solution. Eventually the ketogenic diet evolved, to mimic some metabolic aspects of fasting. It's still used, especially for children who do not respond well to anticonvulsant medications. One undesirable side effect of the diet on children is weight loss. Careful attention must be paid to children on this diet to be sure they maintain enough food intake to support growth and maintain weight. It's that undesirable side effect that brought the ketogenic diet to the attention of dieters. Now it's promoted as a miracle cure for obesity.

This extremely restrictive diet creates a metabolic state called ketosis. Severe carbohydrate restriction shifts metabolism to fat burning for energy needs. People with Type 1 diabetes are familiar with ketosis, as it signals insufficient insulin and poor glucose control, forcing fat metabolism for energy needs. The by-products of so much fat metabolism are ketones, which are quickly flushed out by the kidneys to prevent toxic build-up. One other side effect: appetite suppression, a benefit for dieters. You end up eating fewer calories than you need, and the deficit leads to weight loss, as fat is preferentially burned for energy needs.

The ketogenic diet is extremely restrictive, to push metabolism into ketosis. As a percent of calories, the diet is:

All typical carbohydrate foods are prohibited, aside from certain green vegetables in small amounts.

Contrary to popular belief this is not a high protein diet. At 20% of calories, protein is actually limited to a modest amount. For example, for a 1600 calorie daily intake, protein would be 80 grams, or about 25 - 30 grams for each of 3 meals. That's roughly a 4 oz portion of meat, not a giant steak. And the protein must be restricted that way to make room for the required fat intake.

The permitted food list is very specific, and most of the foods are high-fat:

Very small amounts of watery, low-carb vegetables like greens, broccoli, mushrooms, cucumbers, peppers, zucchini, tomato and broccoli are permitted.

Carbs need to be counted to keep the number at 5% of calories. The 1600 calorie diet would allow for 20 grams of carbs. If you ate 2 tablespoons of peanut butter, which has carbs, you could add 1/2 an avocado and 1 cup cooked spinach. That's it for carbs. All of your other foods would have to come from the list above.



There are several significant problems with this diet:


A ketogenic diet isn't going to cost that much more or less than your normal groceries. You aren't expected to purchase special branded meals or products. All foods are available at any supermarket. Working with a registered dietitian on diet planning and follow up would add modestly to the overall cost.

Social Support

There is no organized ketogenic diet organization to provide support or advice. There are websites, many of which are set up to sell you products. You might find grass-roots support groups in certain places, but there is nothing official. If you do not work with a medical professional, you'll be on your own to find information and prepare food.


Does it work?

Yes it works if you successfully transition to ketosis and stick with the diet long enough to lose weight.

Who would most benefit from this diet?

Obese people who have not had good success sticking to simple low calorie diets with more liberal food choices might do well with these very clear restrictions. Sometimes people are relieved to just have a simple list of what they can eat, omitting choice from the weight loss equation. Also, people who are motivated by seeing the number on the scale go down more quickly than a pound per week might like this diet. So in general, people who are motivated by results and who do better with less choice, and who don't mind the socially isolating nature of this diet might benefit.

Is it viable long term?

No, it is not. It's nutritionally unbalanced and supplements cannot make up for all those deficiencies. Since weight loss is a new application for this diet, and few people stick to it long term, there is little data on what a ketogenic diet might mean for future health.

Do I like this diet?

I wouldn't go on a ketogenic diet myself, but I realize many obese people have found weight loss success with it. My advice is to work with a professional who understands the health implications of the diet and can help you successfully transition off of it after your weight goals are achieved.


Ketogenic diets are now being used for other brain diseases. The Charlie Foundation provides information about ketogenic therapy for seizures, and the website has recipes and information that would be useful to people on ketogenic diets for weight loss.

Medical News Today has some facts on ketosis.

Here is a lengthy scientific review of ketogenic diets for weight loss from the National Library of Medicine.

Weight Loss->Diets
Donna P Feldman MS RDN is author of "Feed Your Vegetarian Teen", writes about food and nutrition at Radio Nutrition and is co-host of the Walk Talk Nutrition podcast series.
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