Here at EBL, we’ve spent plenty of time writing about the evidence on obesity -  and for good reason: millions of Americans are considered obese, which leads to diseases like diabetes, heart disease and cancer.

While obesity is proven to be dangerous, in the past some researchers thought there was a cohort of obese individuals – those without metabolic problems – that didn’t suffer from the negative health effects of obesity. Now there is new evidence on the topic.

A systematic review published this week in the Annals of Internal Medicine addressed the question of whether obesity alone leads to health problems, or if other metabolic factors must be involved. The other factors – often called “metabolic syndrome”- include high blood pressure, high blood sugar, high lipids and a large waist.

For the review, researchers analyzed 8 studies, which included more than 61,000 people, to determine which factors resulted in the greatest risks for heart disease and death.  They found some interesting results.

All of the obese people in the review had an increased risk for heart disease or death, even if they did not have symptoms of metabolic syndrome. For obese participants without metabolic syndrome, the risk of heart disease and death increased when they were followed for 10 or more years.

In addition, normal-weight participants who showed the symptoms of metabolic syndrome had an increased rate for heart disease and death, even though they weren’t obese.

The take-home message: obesity is a serious health threat, even if problems don’t appear initially. Eating healthy foods and exercising are important factors in maintaining health.