NASHVILLE - A man in Nashville, Tennessee, set out to lose weight in a most unusual way — eating only McDonald’s food for 100 days straight.
Kevin Maginnis, 57, a father and grandfather, decided he needed to lose weight after tipping the scales at 238 pounds in February.
Now, just 100 days later, Maginnis is down 58.5 pounds.
Maginnis joined "Your World Cavuto" on Thursday to celebrate his 100th day on his unconventional diet and his remarkable progress.
A McDonald?s Big Mac and chips are pictured at a McDonald?s restaurant beside their headquarters in Munich, southern Germany 27 February 2007. Bane Knezevic (not in picture), president of the western division of McDonald's Europe and chairman of McDo
"Three meals a day, every day, for the last 100 days, nothing but McDonald’s," he said.
Maginnis described his diet this way: He said he eats McDonald’s meals three times a day, but he eats only half of what he orders.
For example, in the morning Maginnis will order two burritos and a hash brown or muffin.
Then, he eats one burrito and half of the hash brown or half of the muffin for breakfast — saving the rest for lunch.
For dinner, he might order a Big Mac meal and eat half the burger, half the fries and half the apple pie — saving the rest for the next day.
"Save [the] other half for the next meal, rinse and repeat, and it’s been absolutely amazing," he said.
Maginnis has not only shed pounds — he said he also has healthy blood pressure and good cholesterol.
His cholesterol dropped 65 points, he noted, and he said his blood pressure is "one of a teenager."
"Every way, you can measure me healthier," he said.
With that many McDonald’s visits over the last 100 days, Maginnis said he is quite the frequent customer.
"There are McDonald’s [locations] that know me," he said.
His wife was so impressed with his diet results that on day 40 of his diet, she decided to join him in the challenge.
Now, 65 days in, she’s down 18 pounds.
Maginnis said the key is to eat half a plate to lose the weight and a third of the plate to maintain the weight.
Lindsay Allen, MS, RDN, a Florida-based dietitian specializing in metabolic health and weight loss, told Fox News Digital earlier that she perceived a couple of 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 said 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."
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.
"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.
Yet Maginnis on Thursday said that having lost the weight, he plans to start a different 100-day challenge — increasing his "beast."
He will start focusing on some fitness goals while incorporating cold plunges into his routine.
He also has plans to climb a 100-foot rope 100 days from now.
As for what he’s doing to celebrate, Maginnis said he’s looking forward to eating a filet mignon tomorrow.
Melissa Rudy of Fox News Digital contributed reporting.