A 57-year-old man from Nashville, Tennessee, is eating nothing but McDonald’s for 100 days in an unconventional attempt to shed some pounds.

Kevin Maginnis is documenting his journey on his TikTok account at @bigmaccoaching. 

His plan is to order three meals a day from McDonald’s, eat only half of each one — and save the other half for his next meal.

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"I woke up this morning and weighed in at 238 pounds," Maginnis said in his first video on Feb. 21. "I decided that is absolutely unacceptable."

He added that although many people will think he's crazy, he's decided to eat only McDonald’s fast food for the next 100 days — while practicing portion control.

Man at McDonald's drive-thru

A man from Nashville, Tennessee (not pictured), is eating nothing but McDonald’s for 100 days in an unconventional attempt to shed some pounds. "I'm 57 years old," he said on TikTok. "I've got kids and grandkids." (iStock)

In another TikTok video, Maginnis shared more about his motivation.

"I’m 57 years old. I’ve got kids and grandkids," he said. 

"I know some overweight 60-year-olds, but I don’t know anyone who’s overweight at 80 years old. I want to be here as long as possible, and I think getting some of this excess weight off is going to help me do that."

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Ten days into his journey, Maginnis has already lost 12-½ pounds, down to 225.5 from 238, he said.

In his videos, Maginnis shares what he orders each day, complete with rhyming puns ("can eating a McGriddle make you little in the middle?"). 

Ten days into his journey, Maginnis has already lost 12-½ pounds.

His go-to meals include the sausage egg and cheese McMuffin with hash browns, the McGriddle with Canadian bacon, the bacon double Quarter Pounder with cheese, chicken McNuggets with fries, and a McChicken inside a McDouble (all cut in half, of course).

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He even indulges in the apple pie and hot fudge sundae, but opts for water instead of soda.

His McDonald’s experiment has garnered nationwide attention — and a growing number of TikTok followers, at 20,600 and counting.

Fox News Digital reached out to Maginnis for comment.

Hamburger and french fries

Some of Maginnis' favorites items from McDonald's include the sausage, egg and cheese McMuffin, the bacon double Quarter Pounder with cheese, and chicken McNuggets with fries. (Getty Images/iStockphoto)

As followers watch his journey, people have been offering up helpful tips, from creative menu suggestions to the best ways to reheat leftovers. (One tip Maginnis received: Use an air fryer instead of a microwave to avoid soggy french fries.)

Maginnis also shares videos of his daily weigh-ins, which have shown a consistent downward trend since he started his new diet plan.

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Ultimately, Maginnis said he aims to prove that people can lose weight by eating only McDonald’s if they control their portions.

"It’s not so much what we’re eating, but it’s the quantity that we’re eating that really jacks us up," he added.

Drive-thru diet won’t serve up lasting results, says dietitian

Lindsay Allen, MS, RDN, a Florida-based dietitian specializing in metabolic health and weight loss, sees a couple of key problems with the fast food meal plan. 

"Eventually, the person's metabolism can drop up to 30% when they restrict calories for too long," she told Fox News Digital via mail. 

"Then, when the person starts eating normal portions again, they will regain the weight right away. This is exactly why fad diets and calorie-reduction diets fail."

A dietitian said that a Nashville man's fast-food diet plan will likely not result in long-term weight loss. (iStock)

The second problem, Allen said, is that Maginnis is missing out on key nutrients that the body needs for optimal health, which can lead to heightened food cravings. 

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"When the brain senses that the body isn’t getting enough key nutrients and minerals, it will ramp up hunger hormones in an attempt to take in more essential nutrients," she said.

"If you give your body nothing but cheap, processed food, it’s going to sense this and encourage you to take in more food."

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Ultimately, Allen said, Maginnis is simply practicing calorie restriction to prove that weight loss is possible no matter what you eat. "Technically, he's correct, but this only works short term and will end up in failure down the road."