Keto diet: The good, the bad and the ugly


If you've been trying to lose weight, you may have stumbled upon the popular keto diet. Many of its followers don't know that this diet was developed by doctors in the 1920s to help manage seizures in children with epilepsy.

The original keto diet was very restrictive, with followers dividing their total caloric intake in this way:

  • 70 percent from fat.
  • 25 percent from protein.
  • 5 percent from carbohydrate.

You may be lured by the promise of quick weight loss on the keto diet, but you should know what you're getting into before you begin this — or any — diet.

Keto diet: The good, the bad and the ugly

"Keto is quite extreme," said Kristal Burton, a registered dietitian nutritionist and certified diabetic educator at NOAH, a community services arm of HonorHealth in the greater Phoenix area. Odds are that anyone you know who claims to be on the keto diet isn't following it precisely. What they're probably following a low-carb or high-protein diet. "Most people are really doing a modified Atkins diet," Burton said.

Here's the good, the bad and the ugly about the keto diet.

The good

It can be fun. If you start the keto diet, you may find you're able to eat large amounts of high-fat foods such as bacon, cream and butter.

You may lose weight quickly. Because you're not eating carbs, your body will begin to use energy from stored fat in your body.

You may break bad habits. If your diet was carb heavy before, you may find you return to a more moderate carb level after you end the keto diet.

The bad

You may feel sick. During the first two to four weeks of the keto diet, you may experience something called the keto flu. Your body may develop flu-like symptoms as it burns the last of the available sugar and transitions to burning fat.

The weight you lost is just water. Although you may feel an initial excitement about losing weight quickly, Burton says it is most likely just water weight from the glucose your liver stores in your cells.

You're creating an unhealthy relationship with food. Burton said that restrictive diets like the keto diet create a cycle of restriction and overconsumption. When you finally allow yourself to consume the forbidden foods, you're likely to overeat — and gain weight.

You'll probably get constipated. Higher-fat, lower-fiber diets can cause constipation, which adds more discomfort to an already difficult-to-follow eating plan.

It's not sustainable. Highly restrictive diets — unless medically necessary — are not realistic for most people for the long term. Eventually you'll probably find it too hard to follow.

The ugly

You could be putting your health at risk. The keto diet is high in fat, including more harmful saturated fat. Burton said that studies have shown that if you eat a diet high in saturated fat, your risk for heart attack is four times higher than if you ate the recommended amount of saturated fat each day. That amount is between seven to 10 percent of your total calories.

You may develop nutritional deficiencies. When you cut out entire food groups, you miss out on important nutrients essential to your health.

You're going to gain back the weight. "You just lost water, so the weight comes right back as soon as you start eating carbs again," Burton said.

A common-sense approach to weight loss

If you want to lose weight, good old moderation is best. That means eating fatty or sugary foods sparingly and getting most of your calories from protein, fruits, vegetables and whole grains. This diet is easier to stick with over the long haul because it doesn't make certain food groups "bad." In fact, it gives you permission to enjoy all foods in a healthy way.

"Eating a balanced diet isn't sexy, exciting or new, but if a diet isn't sustainable, it's not going to work," Burton said.

If you're looking for a sustainable way to lose weight, consult a primary care physician.