During a recent Women's Health interview, Michaels took a stand against the diet, pointing out that it might leave followers without key nutrients.
“I don’t understand. Like, why would anyone think this is a good idea? You know what we need to do? All fat and animal protein!’ No! Bad plan — for a million reasons," she told the magazine in a video. “Macronutrients serve a very important purpose for your overall health and well-being.”
However, Guadagnino, who took on the nickname "keto guido," claims it has worked for him. In May 2018, he said he lost 50 pounds and launched the Instagram page @ketoguido. On Jan. 12, he responded to Michaels with a before-and-after photo, adding, "Sorry Jill."
On Sunday, Guadagnino took part in the "How Hard Did Aging Hit You Challenge" and shared another before-and-after photo.
"As you know from all the before and after pics on this profile, I’ve had some fat unhealthy years in between ... eating natural fat , protein, and veggies instead of processed sugar and carbs has brought me back to 21," the 31-year-old wrote.
Guadagnino also celebrated getting back to the gym after Christmas, sharing a photo from the gym on Dec. 30.
"It’s always been tough for me to work out as well in the midst of eating bad during the holidays but this time I sucked it up and said f– your negative thoughts and work the fuck out because Christmas is over," Guadagnino wrote. "And after the rest of the week of sweating, intermittent fasting, and eating Keto .. I feel good again .... point is, sometimes it just takes a few days of kicking your ass back into gear and then you get back into the flow. Now I intend on doing this consistently for weeks straight and feel better and get more cut as time goes on. Thank God for a sustainable and enjoyable way of eating to always fall back on as a foundation in between little treat holidays."
Guadagnino is not the only celebrity showing support for the keto diet after Michaels' comments.
"So [Jillian Michaels] 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," Today Show meteorologist Al Roker tweeted on Jan. 10.0comments
“My point is, what works for you, works for you,” Roker further explained 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].”
The ketogenic diet involves lowing your carbohydrate intake and increasing fat intake to make your body more efficient at burning fat for energy.