Weight Loss May Not Necessary for Better Health

Historically, researchers have touted weight loss for its health benefits. Whether you have high blood pressure, diabetes or high cholesterol, the typical advice is to lose weight. And there are good reasons for this. For example, some research suggests that 65% to 78% of people with high blood pressure have a greater body fat percentage, and they might benefit by reducing their body fat.  

Other studies have shown split results. We previously reported on research that suggested that compared to participants with low physical activity and no weight loss, those with high physical activity levels plus weight loss had a significantly lower risk of cardiovascular events. But this same study also showed that weight loss alone, without regular physical activity, did not show a statistically significant reduction in the risk of having a cardiovascular event.

Researchers from Harvard were hoping to clear up some of the confusion regarding weight and health, so they examined the significance of weight loss on certain biomarkers of health. They published their findings in the European Journal of Preventive Cardiology.

How Was This Study Conducted?

Researchers drew and pooled data from three previously conducted Israeli nutrition studies: DIRECT, CENTRAL and DIRECT-PLUS. In these studies, a total of 761 participants were randomly assigned to one of several diets, including low-fat, low-carb, Mediterranean or green Mediterranean diets. They also underwent metabolic assessments throughout their study periods, which ranged from 18 to 24 months. 

Some of the biomarkers assessed during the studies included weight, body fat percentage, waist circumference, blood pressure, cholesterol, abdominal (visceral) fat, inflammatory markers and hormones, including insulin and leptin (which helps regulate appetite).  

What Did This Study Find?

At the end of the study participants fell into one of three categories: those who lost more than 5% of their body weight (36%), those who lost up to 5% of their body weight (36%), and those who lost no weight or even gained some (28%). The researchers deemed that last group “weight loss-resistant.”

Researchers examined the connections between the amount of weight lost and the change in biomarkers and found that weight loss was associated with improvements in biomarkers. Specifically, each kilogram lost was associated with a:

• 1.44% increase in HDL (helpful) cholesterol
• 1.37% decrease in triglycerides
• 2.46% decrease in insulin
• 2.79% decrease in leptin
• 0.5-unit reduction in liver fat

There were also reductions in blood pressure and liver enzymes. 

But that’s not all. Even those who didn’t lose any weight saw improvements in some of the biomarkers, including higher levels of HDL (good) cholesterol, lower levels of leptin, and reduced levels of abdominal fat. How can this be? 

“These are deep metabolic shifts with real cardiometabolic consequences,” says Anat Yaskolka Meir, Ph.D., one of the study authors, in a press release. “Our study showed that a healthy diet works, even when weight doesn’t shift.”

Meir goes on to say that many of us have been conditioned to believe that health is all about weight, and that those who have trouble losing weight are doing something wrong—and may even be labeled as failures. “Our findings reframe how we define clinical success. People who do not lose weight can improve their metabolism and reduce their long-term risk for disease. That’s a message of hope, not failure,” says Meir.

In addition to the biomarkers already mentioned, researchers also examined DNA methylation sites and discovered 12 that may be able to predict long-term weight loss. DNA methylation sites work like switches to turn genes off and on. 

“This novel finding shows that some people may be biologically wired to respond differently to the same diet,” says Iris Shai, Ph.D., principal investigator of the nutrition trials and adjunct professor of nutrition at Harvard Chan School. “This isn’t just about willpower or discipline—it’s about biology. And now we’re getting close to understanding it.”

One limitation of this study is that 88% of participants across all three original studies were men. Because of this, it is unknown if these same results apply to women. Also, the three original studies were of varying lengths, which can influence the end results. Lastly, researchers did not look at individual diets and how well participants adhered to them. Nor did it consider other lifestyle behaviors, like physical activity, and their influence on biomarkers. 

How Does This Apply to Real Life?

If you’ve struggled to lose weight or maintain a healthy weight, you’re not alone. Approximately 31% of American adults have overweight, and over 42% have obesity.

While many factors influence weight and weight loss, this study highlights two important factors. First, following a healthy eating pattern may help improve biomarkers, whether weight loss occurs or not. Second, researchers are getting closer to understanding why some people tend to be weight-loss resistant by discovering DNA methylation sites that may be able to predict long-term weight loss. 

Because researchers didn’t evaluate each individual diet and instead lumped them all together, we can’t say which ones showed the most benefit. However, we know the Mediterranean diet has consistently shown health benefits, including for brain health, eye health and bone health. Plus, it’s got a long-running streak of being named the healthiest diet overall.

You can start incorporating foods common in the Mediterranean diet by adding them to your meals and snacks. This includes fruits, vegetables, whole grains, nuts, seeds, legumes, seafood and healthy fats, like olive and avocado oils. If you’re ready to dive in, try our weeklong Mediterranean Diet Meal Plan for Beginners to get started.

We also know that physical activity has been shown to have a plethora of health benefits, even when weight loss doesn’t occur. This includes everything from reducing breast cancer risk and insomnia to lowering dementia and heart disease risk. And while you are ideally hitting the minimal 150 minutes of moderate or 75 minutes of vigorous physical activity each week, there is evidence that much smaller amounts of movement or physical activity squeezed into one or two days can also have benefits. For example, exercising once a week may reduce diabetes risk or help you live longer. Moving more and sitting less may reduce your heart disease risk. And walking after dinner may reduce the risk of constipation. 

Not to be outdone, other health habits also play a role in health. For example, irregular sleep has been linked to a significantly higher risk of diabetes. Even your social life plays a role, as loneliness may increase your risk of dementia. 

Our Expert Take

This study suggests that while weight loss is significantly related to improved biomarkers, those who didn’t experience weight loss but followed a healthy eating pattern also gained significant health benefits. Engaging in health habits, like eating a healthy diet, getting regular physical activity, managing your stressors, getting enough quality sleep and spending time with loved ones, will all go a long way toward reducing disease risk, even if you don’t lose a pound.