The Training Edge Weight Loss Specialist Nutrition

Does It Work for Weight Loss?

National Academy of Sports Medicine
National Academy of Sports Medicine

0212_facebook.PlateOur experts take a look at the latest weight-loss trends your clients are asking about—and bring you smart answers to share.

By Joe Kita in NASM’s The Training Edge, May/June 2014

Americans spend more than $60 billion annually trying to lose weight, but confusion reigns. That’s why we enlisted the help of two top weight-loss experts: Dominique Adair, MS, RD, president of Adair Fitness and Nutrition in New York and Los Angeles, and Chris Mohr, PhD, RD, co-owner of Mohr Results in Louisville, Ky., and a consulting nutritionist with the Cincinnati Bengals. Their mission: Answer the does-it-work question for six popular weight-loss trends. For clients looking to trim their bottoms, here’s their bottom line.

Weight-Loss Supplements

These are the proverbial apples in weight-loss Eden—always in season, always tempting. Their names vary, but their promise is always the same: Ingest to stimulate metabolism and fat burning and get lean.

■ Does it work for weight loss? “Buyer beware,” says Adair. “These supplements fall into two categories: Benign/pointless and potentially dangerous. Public health studies demonstrate that about 20% of drug-related liver injuries that result in hospital visits can be attributed to dietary supplements. While this is not based solely on weight-loss supplements, the light regulation surrounding supplements makes the consumer very vulnerable to those that promote fast, easy fat loss.”

“The fact that these products keep being pulled off the market by the FDA answers the question,” says Mohr. “Many of them can also elevate blood pressure, which is something you don’t want to do if you’re overweight, already hypertensive, and starting an exercise program.”

Intermittent Fasting

One popular approach to this trend espouses periodic fasting for 16-hour periods. Nothing but coffee, tea, and water from 10 p.m. until 2 p.m. the following day; then eat all the nutritious food you want before either repeating the cycle or returning to a normal eating schedule. The promise: Boost metabolism, improve insulin response, and burn more belly fat.

■ Does it work for weight loss? “The premise is that you are preventing the body from getting used to a steady amount of energy, sort of metabolically disarming the body,” explains Adair. “But what’s probably happening is that you’re simply decreasing your average calorie intake over time, which will result in weight loss. Keep in mind that healthy bodies need a healthy amount of food on a regular basis for disease prevention, athletic performance, and cognition. Intermittent fasting doesn’t really align with this objective.”

Mohr agrees: “I always base my weight-loss advice on what the majority of research is showing, and there’s a ton of research suggesting that eating a quality breakfast—30 grams of protein along with other key nutrients—is most effective for losing weight. This approach is also sustainable long-term. People already feel so restricted with their diets. Why give them even more restrictions?”


Two recent studies—one in the British Journal of Nutrition and the other in the International Journal of Obesity—found links between some strains of probiotics (beneficial microorganisms that are either the same as or similar to microorganisms found naturally in the gut) and weight loss. The first study in particular found that overweight people who took a daily drink of 7 ounces of fermented milk fortified with a probiotic lost 8% to 9% of their visceral fat over a 12-week period.

■ Does it work for weight loss? “Probiotics and the whole microbiome is the next big frontier in nutrition,” says Mohr. “I believe they play a big role in the overall health of our bodies. But the research regarding weight loss is preliminary, and I don’t think it’s a magic bullet that will make pounds suddenly fall off.”

Adair agrees: “The data on probiotics and gut health is plentiful across a wide range of GI disorders, but not for weight loss. The jury is out.”

Nonetheless, adds Mohr, “foods that contain probiotics such as Greek yogurt and cottage cheese are very nutritious and high in protein. Including them in your diet is a wonderful thing, whether or not they pan out for weight loss.”

Sugar Substitutes

Sweet’N Low, Equal, Splenda, Truvia … these are all brand names of various sweeteners. Because they’re low- or no-calorie, they’re believed to promote weight loss by deleting the calories that would otherwise be consumed in calorie-containing sweeteners like sugar and honey.

■ Does it work for weight loss? There are three prevailing theories. “The first,” says Adair, “suggests that having an occasional diet soda to replace the calories that would otherwise be consumed may result in an energy deficit that promotes weight loss.”

Then there’s theory number two, also known as the Backfire Theory. “There’s some emerging data,” explains Mohr, “that suggests these products may trick the body into thinking it’s getting something sweet, but when that energy doesn’t materialize for the brain and muscles, cravings arise that cause overeating later.”

Both Adair and Mohr subscribe to theory number three: “These additives belong to a category that the government has labeled GRAS, or Generally Recognized as Safe, which means they have been tested and a determination has been made that in moderate consumption they do not cause harm,” explains Adair. “But just because something doesn’t harm you does not mean it should be included in the diet. There are plenty of studies demonstrating that water and even tea and coffee have a positive impact on disease prevention, but I can’t find one demonstrating any health benefits of artificial sweeteners (other than perhaps weight-loss potential). Better choices—and ones known to prevent disease and promote health—are water, flavored seltzer, or decaf teas, which will help you reach your weight-loss goals and avoid disease.”

Hot Exercise

It started with Bikram yoga, which is done in a stifling 105°F room. Now there’s hot cycling, hot Pilates, and even hot weight-lifting. The premise is straightforward: The more you’re sweating, the harder you’re working, and the more calories you’re burning.

■ Does it work for weight loss? “There’s nothing inherently fat-burning or truly weight-loss inducing about exercising in the heat. One concern is the potential for dehydration with this type of exercise. In fact, the weight loss from fluid loss may be misunderstood by some to be true fat loss,” says Adair. “If you step on the scale before and after one of these sessions you will weigh less, but that is not a result of an energy imbalance (the explanation for true weight loss). It’s just fluid loss.”

But there is one caveat. “If you really like hot exercise,” says Mohr, “and it makes you work out more frequently than you would otherwise, then it may help you lose weight because you’re consistently exercising, not because hot exercise is magical. Just be cautious and aware of hydration, blood pressure, and heart rate to stay safe.”

High-Intensity Interval Training

For years, exercising for long periods at low intensity was believed to be the best way to burn fat and get lean. But then the baby boomers started aging, knees and hips began wearing out from all the running and cycling, and the focus shifted to achieving the same results more safely and efficiently. High-intensity interval training (HIIT) is not something new; it has been around in various guises (mostly for elite athletes) for decades and is backed by research. It’s only lately, however, that it’s being seen as a viable weight-loss alternative for the masses.

■ Does it work for weight loss? “Any kind of exercise, whether it’s low intensity for long periods or high intensity for short periods will improve health,” says Mohr, “but HIIT is more efficient for fat loss because you burn more calories in a shorter period while preserving muscle mass. Everybody can do it too. When we’re fit and think of HIIT, we picture doing hill sprints and 100-yard dashes. But we need to remember that just walking a bit faster for 30 to 60 seconds can really ramp up the heart rate of some people. It’s relative.”

“While it’s appealing to think there’s one particular intensity or zone that’s always better for burning fat than another, it’s simply not true,” adds Adair. “That being said, the top complaint among people who either don’t exercise or don’t exercise enough is they don’t have the time. So HIIT can be their answer. Still, you have to be very careful about recommending a classic HIIT program to a sedentary person, or you risk turning them away from exercise for good. Everyone’s HIIT is different. Trainers need to take the time to establish a baseline and work from there.”


Become a Weight-Loss Expert

NASM’s Weight Loss Specialization (WLS) is designed to help you boost your client base and apply the most up-to-date, respected weight-loss guidelines and training methodologies using the Optimum Performance Training™ (OPT™) Model. For more information and to register, visit


Dominique Adair, MS, RD, is a self-described “jumping bean” who’s very active and maintains her weight by eating a varied and healthy diet. A gain of 60 pounds while pregnant gave her insight and a chance to practice what she preaches.

Chris Mohr, PhD, RD, was overweight as a kid. “For eighth-grade football, I had to lose 20 pounds to make the weight limit. From that point on, I read everything I could find about food and fitness.”

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National Academy of Sports Medicine

National Academy of Sports Medicine

Since 1987 the National Academy of Sports Medicine (NASM) has been the global leader in delivering evidence-based certifications and advanced specializations to health and fitness professionals. Our products and services are scientifically and clinically proven. They are revered and utilized by leading brands and programs around the world and have launched thousands of successful careers.