As far as weight loss goes, trying to get rid of excess body fat is not only always top of mind for those who are overweight or obese, but also lean people who are looking to tone up and stay healthy. However, new research out of T.H. Chan Harvard School of Public Health has revealed that losing weight is best recommended healthwise for those who are obese or medically in need of it. Those who are slim and intentionally trying to shed off a few pounds don’t enjoy such health benefits as they’re more likely to be at increased risk of type 2 diabetes and longer-term weight gain.

The findings reveal that obese individuals who lose weight deliberately have long-term health benefits such as less weight gain and lower type 2 diabetes risk, regardless of whatever means they use to reach weight loss

Qi Sun and his team arrived at these findings after analyzing over 200,000 participants in the journal published in PLOS Medicine.

Study Methodology

The researchers looked at data from 3 prospective cohorts conducted between 1988 to 2017: the Health Professionals Follow-up Study (HPFS), the Nurses’ Health Study (NHS), and the NHSII. The studies involved over 200,000 participants whose ages ranged from 24 to 78 years and consisted of mostly women.

To keep their analysis across the 3 cohorts uniform, they grouped different methods used to lose roughly 10 pounds of weight into seven categories: low-calorie diet (LCD), exercise, low-calorie diet plus exercise, fasting, commercial weight loss program (CWLP), pill and a mix of fasting, commercial weight loss program and pill (FCP).

The researchers gathered data on participants’ body weight and diabetes incidence every 2 years. 


Among the different strategies, researchers found that exercise was most efficient in long-term weight management and prevention among obese individuals. In addition to that, they were also less likely to gain weight after 4 years — 4.2 percent less overall average weight than at the start among obese participants, 2.5 percent weight loss among overweight participants, and 0.4 percent in lean people. This was however reversed among the FCP group as obese individuals sustained 0.3 percent weight loss, overweight participants with 2 percent extra weight gain, and lean participants with 3.7 percent extra weight gain. 

During a follow-up period of over 24 years, the researchers also found that type 2 diabetes risk was still lowered among obese people irrespective of whatever weight loss strategy was used. The trend varied from a 21 percent risk drop among the exercise group to a 13 percent drop for people using diet pills.

However, this beneficial trend was seen reduced among overweight people and the opposite for thin people. For thin participants, the study authors found that all weight loss was linked to a higher risk of type 2 diabetes — ranging from a 9 percent increase among those in the exercise group to a 54 percent increase for the pills or FCP groups.

“We were a bit surprised when we first saw the positive associations of weight loss attempts with faster weight gain and higher type 2 diabetes risk among lean individuals,” says Sun. “However, we now know that such observations are supported by biology that unfortunately entails adverse health outcomes when lean individuals try to lose weight intentionally. Good news is that individuals with obesity will clearly benefit from losing a few pounds and the health benefits last even when the weight loss is temporary.”

Above all, the results show that the link between various weight loss strategies with weight change and type 2 diabetes risk fully depends on the body weight status of the individual before losing weight.

It’s okay to shed off extra pounds when obese but if lean, it could accompany some major detrimental effects on health.

The study concluded with the need for any attempt at weight loss to be fully under medical or health indications.

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