Two recent studies linking obesity, appetite, and the tendency to gain weight to certain genes support something that I have suspected for some time that the familiar “calories-in and calories-out” mantra only tells part of the obesity story. Another part that we’re only beginning to understand is the role genetics and other factors play in body weight.

Here’s the gist of the studies, which were published in Nature Genetics: One reviewed 46 previous studies on the topic of genes and weight and found 18 new genetic regions associated with BMI (body-mass index), as well as confirmed 14 genetic regions previously linked to metabolism, appetite, and other weight gain factors. The second study reviewed 32 previous studies and found links between 13 genes and a genetic tendency to gain weight around the abdomen, which greatly increases risk of metabolic syndrome and conditions such as heart disease and diabetes. The bottom line of both studies: The more of these genes a person had, the more likely he or she was to struggle with weight.

I’ve definitely seen examples of these findings in real life. For instance, one medical student I knew would eat a huge breakfast, followed by five slices of pizza for lunch, and then an enormous dinner. And yet I noticed despite his calorie intake he never seemed to gain an ounce.

Likewise, I have had patients who were very overweight, but claimed to not eat much more than others in their family, like siblings, who did not have a weight issue. When monitored it indeed proved to be true. Despite their similar environment and eating the same foods at every meal, one person would gain weight while another didn’t.

Another patient I knew reported her weight started to skyrocket at puberty. When we examined her more closely, we found that she had a very large non-cancerous ovarian tumor that was wreaking havoc on her hormones. After surgery to remove the growth, her body weight dropped dramatically.

The bottom line is that calories and activity level are just two factors of many that determine a person’s body weight. Other studies have found that a person with one obese parent has a 40 percent higher chance of being obese. Someone with two obese parents has an 80 percent greater chance.

So what does this mean if you happen to be one of those people who seem to gain weight more easily than others? Should you just give up and accept your fate? Is it inevitable that you will gain weight no matter what you do? Absolutely not! But it does mean that like anyone with a genetic tendency toward a certain medical condition, you will need to be extra vigilant about monitoring your health and take steps to avoid your genetic predisposition getting the better of you.

One just needs to look at other genetic conditions for a case in point. A small number of people have a genetic tendency toward extremely high cholesterol levels. If they took no steps to manage their condition, by the time they were in the 20s they could already be suffering life-threatening heart disease and would almost certainly die at a young age. Yet, if these same people knew early on of the risk and took steps to manage their cholesterol along with close medical supervision and medication if needed, they could control their cholesterol levels and lead a long and healthy life.

That’s why I feel it is so critical for people to recognize obesity as a medical condition. They need to let go of stigmas that say it’s about lack of willpower or some kind of personal shortcoming, and to stop risking their health with diet plans that offer a temporary quick fix but don’t really address the core issues. Like any chronic health condition, obesity can be managed with the proper medically supervised diet and exercise programcombined with medical treatment for any underlying health or hormonal issues that may be playing a role in weight gain.

So no matter how many times you have tried to lose weight, don’t lose hope. But also, don’t try to do it alone. Just like you wouldn’t try to treat heart disease on your own, you shouldn’t try to tackle a complex and possibly life-threatening health problem like obesity yourself either.