Kevin Smith Loses 20 Pounds On All-Potato Diet

After suffering a heart attack on February 25, actor/filmmaker/podcaster Kevin Smith decided to get serious about weight loss. Some people go plant-based to try to get healthier, but Smith took it one step further: he went potato-based.

For two weeks, Smith ate an all-potato diet. Mashed, boiled, or steamed — didn't matter, so long it was 100 percent potato.

Smith got the idea from a book called Presto!: How I Made Over 100 Pounds Disappear and Other Magical Tales, wherein magician Penn Jillette revealed how he lost weight with a diet that's received more than a little criticism from health professionals.

The plan, called the "mono diet," involves choosing one food to eat and eating only that food for a period of two weeks. Jillette chose potatoes "because they're funny," he wrote on Grub Street. "Could have been corn, could have been beans, but I didn't want a lot of fart jokes." Once the two weeks were over, he introduced salads (without fruits or nuts) and vegetable soups alongside the starchy vegetable.

"The desperation of wanting to lose weight — and see results quickly — will lead people to choose a plan that makes no biological sense," Madelyn Fernstrom, NBC News Health and Nutrition Editor, told Today when the book was released in 2016. "This is not an advisable plan."

"It's a pretty intense program, but it's been interesting," Smith said on his podcast, Hollywood Babble-On. "And of course necessary for my health and stuff."

On the surface, it does seem that way — if you're judging his health on whether or not he's lost weight. "I'm officially down 20 pounds as of this morning!" he announced on Twitter. "20 pounds in 13 days & my blood pressure is amazing."

But health experts aren't as enthused about his progress.

"As with many other diets, weight loss is inevitable and generally straightforward in the early stages," said nutritionist Julie Mancuso to The Daily Meal. "Sustaining such weight loss on a long-term basis is usually the challenge."

Mancuso says this can happen when people deprive themselves to the extreme — like, say, by omitting all foods except potatoes — and their nutrient-deprived bodies begin to rebel.

"With that said, potatoes are beneficial in a number of ways," Mancuso added, noting their impressive iron, calcium, zinc, magnesium, and vitamin C content alongside some antioxidant properties. "The fact that potatoes contain no cholesterol can also be of great benefit to someone in Kevin Smith's situation," she says.

However, the all-potato diet "it is just incomplete, nutritionally-speaking. Potatoes contain very little protein, which is needed by the body for repair of tissue and cells," Mancuso explains, "And potatoes do not contain fat, which is essential for heart health."

In any case, Smith's weight loss might simply be a function of the amount of food he was eating. "While this diet may result in weight loss, it is due to overall calorie restriction and not the magic power of potatoes," registered dietitian Bari Stricoff told The Daily Meal. "Especially for cardiac health, this diet has no scientific basis or evidence to support it."

Eating only potatoes isn't even that weird, so far as Hollywood goes. Your favorite celebrities probably have some weird diet habits.