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Nutritionists recommend staying away from BMI in weight loss journey

Uniontown Hospital Nutritionist Brittney Zack

By Olivia Goudy


During just about every weight­loss journey, the words “body mass index” play a role, particularly on the clinical side.

Nutritionists, dieticians, physical trainers and physicians have been using the BMI to measure body fat based on the height and weight of an individual.

A local nutritionist agrees with a recent report, however, that BMI might not be the best base or resource for someone looking to lose weight.

“There is not one black­and­white recipe for weight loss,” said Brittney Zack, clinical dietitian at the Uniontown Hospital. “It may not necessarily be the best tool to use for those with weight loss goals.”

An Associated Press report indicated that Ottawa­based physician Yoni Freedhoff moved away from numbers like BMI and body­fat percentage. He preached that perfection was not the aim and that few would lose every pound possible. It was better to focus on more realistic goals, he said.

Zack noted that for those who are successful with their weight­loss battles, they do “so in a manner relative to the person who is achieving it — perhaps quickly and dramatically, or slowly and gradually.” “Regardless, it must be tailored to the individual,” she added. “Someone scheduled for bariatric surgery and someone joining Weight Watchers to shed a few pounds before summer vacation are going to have two extremely diverse weight­loss strategies, as well as two different outcomes.”

“Goals need to be attainable and realistic to the person attempting to reach them, so the chances of not only achieving, but also maintaining, them are higher,” she said.

Freedhoff, also an assistant professor of family medicine at the University of Ottawa, said he isn’t as rigid now as he was before. He also has shifted his weightloss teachings to focus on enjoyment rather than perfection. “We started to use a term I coined, ‘best weight,’” he said in the report. “That’s whatever weight you reach when you are living the healthiest life that you honestly enjoy. When you let go of the numbers, people tend to take more pride in their efforts, and that helps them stick with the efforts.”

As for the role of BMI, Zack said it does have its benefits — one of which is that it “provides a sound nutritional trigger for persons at risk for malnutrition.”

It doesn’t however, accurately determine weights at the opposite end of the spectrum, she said.

Zack also said BMI doesn’t take into account a person’s stature, resulting in “athletes or people with a prominent amount of muscle mass who may have a skewed, higher, BMI.”

Shifting perspectives

Obesity researcher Kevin Hall published a paper in a British medical journal that outlined the trajectory of most weight­loss efforts, further explaining that while it’s possible for motivated dieters to lose a pound to 1.5 pounds per week for the first month or so, that rate soon slows. Hall further explained that, in this case, the initial weight loss comes from a calorie cutback of 700 to 800 calories per day.

Few people can maintain this restrictive eating pattern for long, however. At six months, the average calorie deficit has declined to about 150 calories per day, and the weight soon climbs. After two years, weight has returned to about where it was at the one­month mark of the diet.

“Our findings strongly suggest that weight­loss programs should not be short­term effects,” Hall said. “Rather, they take persistent lifestyle changes. The primary determinant of success is sustained adherence to healthy changes in diet and physical activity.”

Zack said that before an individual begins their weight­loss journey, an understanding that it’s a process needs to happen. “It’s a marathon, not a sprint,” she said. “There are no quick fixes to weight issues, and if one is found, it will likely result in regain — perhaps even to a weight higher than that where the person started.”

“If we could rationalize from the start that weight loss (and maintenance) requires patience and a committed long­term lifestyle change with ups and downs, longterm goals would be much more realistic and thus much easier to obtain.”