Pros and Cons of the Ketogenic Diet
What You Need to Know About Keto
Though it may seem new to your newsfeed, the ketogenic diet has been around since the 1920s. The low-carbohydrate, high-fat diet gained a foothold when proven to reduce seizures in pediatric patients with epilepsy. While still prescribed for that purpose today, the diet is now touted as a weight loss tool.
Breaking Down the Keto Diet
The keto diet is all about cutting carbs and eating more fat. Here’s what the daily breakdown of carbs, protein and fat looks like:
- 5 percent of calories from carbohydrates, including low-carb, non-starchy vegetables and small amounts of leafy greens. The keto diet excludes carb-rich foods like grains, beans, fruits and starchy vegetables.
- 20 percent of calories from protein, such as meat, eggs and cheese.
- 75 percent of calories from fat, such as oils, unprocessed nuts, butter and avocado.
According to Dietitian Richelle Gomez, MS, RDN, LDN, Northwestern Medicine McHenry Hospital, the ketogenic diet is designed to burn fat by cutting carbs. “Your body turns carbohydrates into glucose for energy,” she explains. “When you cut carbs from your diet, you switch to burning fatty acids, or ketones.”
Breaking down fats for energy is called ketosis. It takes about three weeks of carbohydrate elimination for your body to transition into ketosis.
Here are the pros and cons of the keto diet.
“There has been anecdotal evidence of people losing weight on the ketogenic diet,” says Melinda R. Ring, MD, director of Northwestern Medicine Osher Center for Integrative Health. “People also report feeling less hungry than on other types of restricted diets.”
Gomez says people feel less hungry because fatty foods take a longer time to break down in the body. Weight loss not only comes from ketosis, but also from reducing calorie intake by eliminating food groups.
No More Low-Fat
On paper, burning fats by eating more of them is enticing, which is why the diet has become popular. The keto diet allows many people to eat the types of high-fat foods that they enjoy, such as red meats, fatty fish, nuts, cheese and butter, while still losing weight.
Health Benefits for Specific People
The keto diet helps reduce seizures in pediatric patients with epilepsy. Endurance athletes and body builders also use it to scrap fat in short timeframes. The keto diet is being studied for mitigating symptoms for patients with progressive neurological disorders like Parkinson’s disease, but scientific research has not confirmed benefits for these populations.
Difficult to Sustain
Because of the stringent food restrictions, many find the keto diet hard to stick to.
“The ketogenic diet can be effective for weight loss when used in a short time period followed by the adoption of healthier eating habits,” says Cardiologist Kameswari Maganti, MD,Northwestern Medicine Bluhm Cardiovascular Institute. “Unfortunately, it lends itself to yo-yo dieting, which increases mortality.”
Ketosis is difficult to achieve because it’s like a light switch: either on or off. Individuals who consistently track food intake are more likely to remain in ketosis. But the only way to tell if your body is in ketosis is a blood test.
Calorie Depletion and Nutrient Deficiency
“Because the keto diet is so restricted, you’re not receiving the nutrients — vitamins, minerals, fibers — that you get from fresh fruits, legumes, vegetables and whole grains,” says Dr. Ring.
Due to these deficiencies, people also report feeling foggy and tired. These symptoms have been dubbed “the keto flu.” Constipation is also common on the keto diet due to the lack of fiber.
Bad Fats in Practice
The high-fat nature of the diet could also have negative impacts on heart health. The American Heart Association recommends limiting saturated fat intake to 5 to 6 percent. “In practice, many people eat high amounts of saturated fats, which could increase cardiovascular disease risk,” says Dr. Maganti. “We see an increase in lipids, or fats, in the blood of patients on the keto diet within six to eight weeks.”
“Patients with kidney disease have an increased risk of requiring dialysis on the keto diet due to the additional ketones that their renal system has to process,” says Dr. Maganti.
Some people also experience dehydration on the keto diet because they’re eradicating glycogen, which holds water, from their bloodstream.
“When you micromanage your food intake by tracking how much you eat, it disconnects you from what your body is asking for,” says Gomez. “You start using outside numbers to determine what to eat instead of listening to your body.”
Monitoring food so closely can lead to psychological distress, such as shame, and binge eating. Restriction can lead to bingeing, which often leads to guilt, which then leads back to restriction in a continuous cycle.
Both Dr. Ring and Dr. Maganti recommend balanced approaches, like the Mediterranean diet, for long-term weight loss.
“You can still receive the benefits of ketosis while eating a varied and balanced diet through intermittent fasting,” says Dr. Ring.
Gomez advocates making small changes based on your health goals. “All foods fit into a healthy diet,” she says. “It’s a matter of moderation and finding ways to eat the foods you love without overindulging.”