Even doctors agree that there are pros and cons to the keto diet.
Asked what he thought of the low-carb, high-fat eating plan beloved by many celebrities, Dr. Sanjay Gupta tells PEOPLE Now that he does think it’s an effective way to shed pounds in a hurry.
“You can lose a lot of weight and you can do it quickly,” he says.
“The idea is that you’re putting your body into a state of ketosis, that’s why it has its name. You’re not eating any sugar, you’re not eating any carbs, you’re mainly eating fat….so you will lose weight,” he explains.
However, there are a couple of downsides to the diet.
For starters, it can be incredibly difficult to stick to the eating plan for a long period of time.
“It’s very hard to sustain, so it’ll usually be a few weeks and a lot of that weight you lose is water weight,” he explains.
Also, he adds, people with a history of heart disease in their families might want to think twice about consuming so much fat.
“If you’re worried about that sort of stuff, this is probably not the diet for you because you are eating a lot of fat and that’s the concern,” he says.
Critics of the current craze have also claimed the keto diet deprives your body of essential nutrients.
“Your cells, your macro molecules, are literally made up of protein, fat, carbohydrates, nucleic acids. When you do not eat one of the three macro nutrients — those three things I just mentioned — you’re starving yourselves,” celebrity trainer Jillian Michaels said in a video for Women’s Health earlier this year. “Those macro nutrients serve a very important purpose for your overall health and wellbeing. Each and every one of them.”
Michaels previously told PEOPLE TV about her hatred of keto, and urged viewers to do something a little less complicated.
“Do not go keto. Just work out, eat clean and don’t overeat. I promise you, balanced diet,” she said. “It’s that simple.”
Although not everybody is a fan, the keto diet has quite a following, including supporters like Jenna Jameson, Halle Berry, and Al Roker — who has dropped 40 lbs. since starting the diet last year.
Opening up about his weight loss last month, the Today co-host, 64, shared that the high-fat diet hasn’t hurt his cholesterol levels.
“Yeah, my cholesterol, just had it checked out a few weeks ago, everything’s good,” Roker added.
Our very own @alroker has been on the keto diet since September, and he’s sharing some of his favorite, easy keto-friendly recipes with us! pic.twitter.com/feVchveYWs
— TODAY (@TODAYshow) March 4, 2019
In addition to championing the diet, he frequently challenges keto critics.
After Michaels slammed the eating plan, he fought back in tweets and onToday. “So @JillianMichaels says #Keto is a bad idea. This from a woman who promoted on camera bullying, deprivation, manipulation and more weekly in the name of weight loss. Now those sound like bad ideas,” he tweeted.
Michaels challenged Roker to a debate, but he declined.
“My point is, what works for you, works for you,” he added on Today. “There’s science on both sides that says it’s not a great idea and science that says it is a good idea. I think it’s up to people — with their doctor, with their medical professional — [to make their own decision].”
At the end of February, Roker also politely disagreed with a dietitian who tweeted at him that she was “sad to see another famous person falling for a fad diet.”
“Heidi, there are so many sadder things in the world,” he responded. “Have a great day.”