One-Third of “Normal-Weight” Individuals May Actually Be Obese

"Israel is a leader in childhood obesity and more than 60% of the country's adults are defined as overweight," says Prof. Gepner, adding that, "the prevailing index in this respect is BMI, based on weight and height measures, which is considered a standard indicator of an individual's general health. However, despite the obvious intuitive connection between excess weight and obesity, the actual measure for obesity is the body's fat content, with the maximum normal values set at 25% for males and 35% for females. Higher fat content is defined as obesity and can cause a range of potentially life-threatening cardiometabolic diseases: heart disease, diabetes, fatty liver, kidney dysfunction, and more. The disparity between the two indexes has generated a phenomenon called 'the paradox of obesity with normal weight' – higher than normal body fat percentage in normal-weight individuals. In this study, we examined the prevalence of this phenomenon in Israel's adult population."

This study analyzed the anthropometric data of 3,000 Israeli participants that was accumulated over several years which included BMI scores, DXA scans, and cardiometabolic blood markers. Findings indicated that around one-third of the participants were within the normal weight range, of which 38.5% of the women and 26.5% of the men were identified as being “obese with normal weight”- having excess fat content despite their normal weight. 

Further analysis matching body fat percentage with blood markers from the participants identified a significant correlation between “obesity with normal weight” and high levels of sugar, fat, and cholesterol, which are all major risk factors for a range of cardiometabolic diseases. But at the same time, 30% of these men and 10% of these women identified as being overweight were also found to have normal body fat percentages. 

"Our findings were somewhat alarming, indicating that obesity with normal weight is much more common in Israel than we had assumed," warns Prof. Gepner. "Moreover, these individuals, being within the norm according to the prevailing BMI index, usually pass 'under the radar'. Unlike people who are identified as overweight, they receive no treatment or instructions for changing their nutrition or lifestyle - which places them at an even greater risk for cardiometabolic diseases."

The researchers concluded that body fat percentage is a more reliable and accurate indicator of general health than BMI based on their findings and suggest that body fat percentage should be the prevailing standard of health measurement. The team recommended some methods and tools that could be used for this purpose such as skinfold measurements that estimate body fat based on the thickness of the fat layer under the skin, and a device that measures the body’s electrical conductivity, which are already being used in many fitness centers to evaluate health.

Prof. Gepner: "Our study found that obesity with normal weight is very common in Israel, much more than we had previously assumed, and that it is significantly correlated with substantial health risks. And yet, people who are 'obese with normal weight' are not identified by today's prevailing index, BMI. We also found that body fat percentage is a much more reliable indicator than BMI with regard to an individual's general health. Therefore, we recommend equipping all clinics with suitable devices for measuring body fat content, and gradually turning it into the gold standard both in Israel and worldwide, to prevent disease and early mortality."