In a recent interview with PeopleTV, Michaels shared her strong opinion that the keto diet isn't for most people and called it a "diet fad."
"The reason that keto has been getting so much attention is because it helps significantly to manage your insulin levels. Very high insulin, very bad thing," she explained. Because of this, keto works well for people who struggle with high insulin levels, especially those with polycystic ovary syndrome, type 2 diabetes, and infertility, but it's not appropriate for most people, she said. "If you’re not eating a bunch of processed carbs and processed sugar and you’re not eating too much food in general, you won’t have insulin levels that are going through the roof,” she explained.
While the keto diet embraces healthy fats, it severely limits carbs and moderately limits protein. "When you're not eating one of those macronutrients, you are quite literally starving your cells and disabling them from functioning in their proper way," she said, adding that high-fat diets like keto, which has been touted by celebrities like Halle Berry (who has diabetes) and Kourtney Kardashian, may also accelerate aging by increasing the rate at which telomeres shorten.
Those who approach the high-fat diet with the mindset that they "can eat whatever" in any quantity are making a huge mistake, said Michaels. “Calorie management and calorie restriction is less oxidative stress, so it’s far better for aging and being healthier,” she said. "It gives your body more energy to focus on immunity, and a host of other things that keep you healthy and strong for a really long time."
Her advice? The same as it's always been: "Just work out, eat clean, and don't overeat," she emphasised. "I promise you: Balanced diet—it's that simple."
Michaels isn't the first expert to speak out against keto.
The keto diet is a divisive topic among registered dietitians and other health expert. Kristen Kizer, a registered dietitian, says that long-term reliance on ketones—the chemicals produced when your body breaks down fat—for energy could be harmful. "Those ketones are emergency fuel sources, and we’re not meant to run on them long-term," Kizer said. "Ketones are negatively-charged molecules, which means they’re acidic. When you build up ketone bodies in your system, you’re building up acid. One of the ways your body buffers acid is by pulling calcium from your bones." She also said the keto diet isn't very balanced, and because it involves a higher intake of animal products, it offers little protection against cancer, diabetes, and other diseases.
There are some dangerous risks and side effects involved with keto. For example, if ketone levels become too high, you become at risk for ketoacidosis (DKA), a life-threatening condition that occurs when you don't have enough insulin in your body. "Keto flu" is a common side effect of the keto diet, accompanied by symptoms of fatigue, headaches, and pain as a result of dehydration and loss of electrolytes. Other unpleasant effects of keto include higher risk for kidney stones, bad breath, muscle cramps, and dizziness.
In terms of effectiveness for weight loss, some studies suggest that the keto diet may work, but the studies were small, and one study even found that people had higher levels of inflammation and worsened moods. Author and speaker Dorena Rode found that her cholesterol levels actually increased to a dangerous level on the high-fat diet.
Keto is controversial, but it may work for some people.
While some experts have expressed concerns about the keto diet, others like the idea of forcing your body to run on a "cleaner" source of energy like ketones, which can boost your mood and energy levels, Lori Chang, a registered dietitian said.
As a weight loss solution, the keto diet is working for some people (the thousands of before-and-after images on Instagram are proof of that), but the lack of sufficient research means there could be detrimental long-term effects. Whether you're already a die-hard keto fan or are considering switching to the high-fat diet, talk with your doctor to make sure it's safe for you.
This article originally appeared in Prevention