Debating Diets: What is the ketogenic diet?

Editor’s note: Debating Diets is a series highlighting pros and cons of dietary trends with expertise from dietitians, nutritionists and healthcare professionals at Baylor College of Medicine.

Exploring the idea of starting a new diet? While the amount of information available can be overwhelming, it’s possible to find a diet that is safe, suitable and effective for your lifestyle.

Luis Rustveld, Ph.D., registered and licensed dietitian with Baylor College of Medicine, kicks off Debating Diets with a discussion about the ever-popular ketogenic (keto) diet.

How does the keto diet work?
Luis Rustveld, Ph.D.

The keto diet relies on significantly lowering carbohydrate intake, typically less than 50 grams per day, thereby forcing the body to rely mainly on burning fat for energy. The process of burning fat for energy results in formation of ketone bodies that the body uses for energy, instead of carbohydrates.

How did this diet become popularized?

Losing weight is difficult, and many people have been desperate to find ways to see results quickly. Any kind of diet that promises that you are going to burn fat and lose 20 pounds in one to two months is attractive.

However, we’re talking about a diet which has been traditionally recommended to treat conditions such as epilepsy and polycystic ovary syndrome – and it has now become a mainstream option. There’s nothing wrong with options, but you have to consider the potential side effects.

What kind of physiological changes or side effects should be expected?

A lot of people complain about bad breath because of excessive meat consumption. More concerning though is nausea, vomiting, muscle soreness, back pain and a general sense of fatigue. It usually takes about seven to 30 days for your body to get used to these kinds of changes.

Insomnia and other sleeping problems are also common. In some cases, we see these symptoms go away. Many times the symptoms are so strong they cause patients to quit the diet. All of these symptoms should be taken into consideration before starting the keto diet.

Who should avoid this diet?

Anyone who requires insulin, like type 1 diabetics, should not do this diet because it is designed to reduce insulin levels in the body.

I’m also surprised that we have so many athletes interested in this diet. When you think about it, high-performance athletes need a lot of energy and require more carbohydrates and micronutrients, but the keto diet can lead to lethargy and malaise, and negatively impact performance. Athletes should consult with their healthcare provider before starting the keto diet.

What are recommended foods? Discouraged foods?

The keto diet requires high consumption of fat, so it should be high-quality fats that you eat.

Monounsaturated and polyunsaturated fats, which include salmon, avocado, nuts, seeds, canola oil, olive oil, and olives, work well with this diet. However, sometimes coconut oil is described as a high-quality fat and is often recommended with the keto diet – I disagree because it is a saturated fat, and therefore can raise blood cholesterol levels.

Non-starchy vegetables like lettuce, tomato, cauliflower and asparagus are great. Other vegetables like corn, potatoes and sweet potatoes are discouraged.

What else should people know before considering the keto diet?

Whenever you are considering a diet that promises results quickly or eliminates an entire food group, you should consult with your healthcare provider – particularly if you have a pre-existing health condition or a family history of heart disease or diabetes.

Also, take into consideration that this diet is not designed to be followed long term. It can be difficult to sustain because of the extreme modifications and symptoms, and many people end up gaining the weight back. Like all diets, it should be directed by your healthcare provider.

Additional Resources

Learn about weight management services at Baylor Family Medicine.

See dietitian-approved recipes.

-By Nicole Blanton

One thought on “Debating Diets: What is the ketogenic diet?


    Carbohydrates directly cause cancer, diabetes, obesity, heart disease, liver disease and dementia.


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