In March, Kevin Maginnis embarked on a 100-day journey to lose 50 pounds by only eating McDonald's. Now that he's finished the challenge, he shared the results on the TODAY show on June 1.

When the 57-year-old started going viral for his unusual weight loss methodology, he raised plenty of eyebrows. But by day 43, he had already lost 33 pounds.

On Thursday, Maginnis stopped by Studio 1A to celebrate the last day of his unconventional experiment and revealed that he'd lost 58.5 pounds. When he started, he weight 238 pounds and he's now down to 179.5 pounds.

“I feel amazing,” he said on TODAY.

Maginnis' methods were quite straightforward: Eat three meals a day from the fast food chain, but cut the portions in half. He also skipped snacks and only drank water, about 80 to 90 ounces a day.

Nothing on the McDonald's menu was off limits — including fries and dessert — and Maginnis didn't work out or count calories during the experiment.

Maginnis said his bloodwork shows that his health has improved. He said he lowered his level of triglycerides, a type of fat that circulates in the body, by 205 points and his cholesterol by 65 points.

Beforehand, Maginnis was prediabetic, but he said his A1C levels (which measures your average blood sugar levels over the past three months) are now in a healthy range.

Halfway through the challenge, Maginnis’ wife, Melody, joined him. In 40 days, she’s lost 17 pounds, her husband shared.

Now that Maginnis has reached his goal weight, the next step is embarking on a workout routine.

"(I plan to) increase the beast in me. We're going be doing an ice plunge. I'm going do a 100-foot rope climb," he said, adding that the latter goal is his "personal Everest."

Maginnis is looking forward to eating a filet mignon on Friday, and he plans to eat three quarters of his meals moving forward to maintain his weight.

Maginnis understands that many people question his methods, but he said the initial part of his experiment was focused primarily on weight loss.

"Are there better micronutrients or macronutrients for brain health? Absolutely. But when it comes to getting rid of obesity, reduce the size of the meals," he said.

TODAY.com previously consulted registered dietitian Frances Largeman-Roth to determine how healthy Maginnis' weight loss approach is.

Largeman-Roth agreed that cutting calories is important, but suggested that anyone looking to shed some pounds focus on a more well-rounded method.

“Even though Kevin is cutting his meals in half, he’s still getting well over the recommended 2,300 milligrams of sodium daily. One bacon, egg and cheese biscuit contains 1,330 milligrams of sodium, and a Big Mac has over 1,000 milligrams without ketchup or mustard,” she explained.

Largeman-Roth also emphasized the importance of physical activity, adding that, without this, weight loss eventually plateaus.

“And let’s remember that health isn’t just about the number on the scale. It’s also about cardiovascular health and other measures,” she added.