Brandon Marshall Lost 13 Pounds on This Diet. Should You Try it Too?

STACK takes a look at the 21-Day Fix, a diet used by NFL wide receiver Brandon Marshall. Is it a good fit for young athletes?

The diet programs featured on TV informercials are typically targeted to stay-at home moms—not to professional athletes. But that didn't stop New York Jets receiver Brandon Marshall from going on the 21-Day Fix, a diet and fitness program that promises significant weight loss in just three weeks.

Marshall saw the infomercial when he was watching television this past off-season and decided to give it a try. The result? He dropped 13 pounds and got down to a weight of 230, his lightest playing weight since 2010. Marshall liked his results, but does the 21-Day Fix diet make sense for most athletes? STACK investigates.

The Diet

Brandon Marshall

The 21-Day Fix does includes a fitness program (30-minute daily workouts), but the diet component seems to be the main selling point—so that's what we focus on here.

The 21-Day Fix diet uses seven color-coded containers of different shapes and sizes. The containers correlate to specific types of food: ; two 8-ounce containers for fruits and vegetables; a 6-ounce container for protein; a 5.3-ounce container for carbohydrates; a 2.7-ounce container for healthy fats and cheese; and two 2-ounce containers for seeds and dressings. You also get teaspoons to measure oils and nut butters.

How these containers are used is determined by your calorie target. Your calorie target is determined by a formula based on your body weight in pounds. You begin with your body weight, multiply it by 11, add 750 and subtract 400. The resulting number is your calorie target for the 21-Day Fix. If your calorie targets works out to be under 1,200, you round it up to 1,200, and if it works out to be higher than 2,300, you round down to 2,300.

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After you find your calorie target, you use a chart to find out how much you're allowed to eat under the diet. The amount of food you're allowed is expressed in terms of the containers—for example, Marshall, who fell in the 2,100-2,300 calorie target group, was allowed to eat six containers of veggies, four containers of fruit, six containers of lean protein, four contains of carbs, one container of healthy fats/cheese, one container of nuts or seeds and six teaspoons of oils or nut butters per day.

A wide range of foods are allowed in the 21-Day Fix diet. Foods that don't necessarily fit neatly into a container (like a slice of bread or eggs) are assigned a number that equals one container-full (one slice of whole grain bread counts as a container of carbs, for example).

What's Good

21-Day Fix

photo from 21-Day Fix official website

The diet's focus on portion sizes is smart and helpful, since many people have a difficult time figuring out the correct quantities to eat without some type of guidance.

Portion sizes have a significant effect on how much we eat. Researchers at the University of Cambridge believe eliminating large portions could help people cut nearly 300 calories a day from their diets. Serving sizes have grown exponentially over the last few decades, and people have an instinctual desire to finish food when it's available.

The 21-Day Fix helps people learn what proper portion sizes actually look like. It eliminates the need to stare at the back of nutritional labels and try to analyze a bunch of numbers. It also helps the 53 percent of people who don't take the time to read serving sizes. In the 21-Day Fix, serving sizes are simple—fill up the container, and there's your serving.

This also circumvents the monotony of counting calories—a time-consuming process that many feel takes too much effort.

Many different foods are allowed under the 21-Day Fix, and it looks like the diet strikes a healthy balance between strict restrictions and unlimited choices. Other trendy diets include eating only bananas or drinking only homemade lemonade, so the 21-Day Fix is certainly an improvement over those diets.

What's Not So Good

21-Day Fix

The basic premise of the 21-Day Fix is that it'll help you lose a significant amount of weight really quickly. That approach isn't the best thing for instilling long-term healthy eating habits.

"I wouldn't be a big fan of advocating this type of eating where it focuses on losing a lot of weight in a short amount of time," says registered dietitian Tavis Piattoly, who works as a nutrition consultant to the New Orleans Saints and New Orleans Pelicans. "A lot of the weight is going to be water and possibly even muscle tissue."

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Yes, the focus on portion sizes is a smart approach, but it's hard to say the changes will stick around after someone finishes the 21-Day Fix. Twenty-one days is an interesting duration, because there is a common saying that it takes just 21 days of performing a behavior for it to become a habit. However, researchers have found that it usually takes someone about three times that long. So going on a diet for 21 days probably won't "fix" your nutrition in the long run. "It might set unrealistic expectations for once those 21 days are up," says Piattoly.

According to the Mayo Clinic, losing weight in a healthy way requires long-term changes. "Losing weight—and keeping it off—is a lifetime commitment," says the Clinic's website. "Weight-loss pills and other quick fixes don't address the root of the problem and could pose risks of their own. Even then, the effects are often short-lived. Without a permanent change in habits, any lost weight is likely to return—and then some."

However, users are encouraged to perform multiple "rounds" of the 21-Day Fix—sticking to the plan for an additional three weeks. In fact, most of the progress pictures on their website show people who performed several rounds of the 21-Day Fix, a fact that's noted in rather small print. But with the heavy emphasis on short-term results, it's hard to say exactly how many people stick with the 21-Day Fix beyond its namesake.

Also, the calorie restriction might be a little steep for certain athletes, especially young ones. Athletes live a highly active lifestyle, and adolescents need significantly more calories than adults to support proper growth. Although a calorie deficit is the key to losing weight, too big of a deficit can cause issues like chronic fatigue and lack of focus. NFL All-Pro defensive end J. J. Watt recently felt the draining effects of a massive calorie deficit and was forced to make some serious diet changes to stay sharp.

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The Verdict

The diet of the 21-Day Fix has a lot going for it. It focuses on whole foods and prioritizes portion sizes over counting calories. If you're an obese or overweight adult looking to change your eating habits, the 21-Day Fix could be a good idea.

"It could be a great jump start for overweight and obese people to feel confident about their weight loss," Piattoly says.

But if you want to form long-lasting health habits with the 21-Day Fix, you probably need to perform multiple rounds.

For young athletes, the 21-Day Fix probably isn't the best way to go about losing weight. Young athletes burn a tremendous amount of calories, and the 21-Day Fix diet is more designed for obese and overweight adults than for active teens. Young athletes who want to change their bodies should worry more about overall body composition than pure weight loss. The bathroom scale is a flawed tool, particularly for athletes.

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If you're a young athlete looking to lose weight, your first step should be to cut down on refined sugar products (soda, candy, etc.) and trips to the drive-thru. Replace those foods with plant-based options and drink more water. If you're eating the right kinds of food, how much you're eating shouldn't be a major issue.

If you're a young athlete looking to change your body, meet with a health professional or registered dietitian. They can help personalize a plan for you instead of using the "one-size-fits-all" approach that many fad diets rely on. And remember—slow and steady progress is often the safest and the most sustainable way to lose weight.

Photo Credit: Getty Images // Thinkstock