A scant century ago, the oldest most men could expect to live was about 46 years of age and 48 for women.

Over the past 100 years, that figure has climbed well into the 70s for men and pushing 80 for women. But now, that century of improving longevity faces an obstacle that threatens to stall — or worse, even reverse — its gains, and it’s not a novel new disease or deadly pandemic: it’s our waistlines.

Being overweight or obese increases the risks for a host of health conditions, including coronary heart disease, stroke, diabetes, chronic kidney disease and several types of cancer, such as breast, colon, prostate and others. And studies have shown that the risk of dying from one of these conditions increases along with our weight.

If the solution was as simple as telling people to put down their forks, we wouldn’t be facing an epidemic of obesity. Our nation’s obesity problem, however, is the product of a host of convergent factors, including the widespread availability of unhealthy foods, technologies that make routine physical exertion less necessary (few of us routinely walk anywhere, after all) and even evolving social norms have contributed to a nation that’s packing on the pounds.

Still, it’s not too late to save the important progress we’ve achieved — and reduce the occurrence of weight-related diseases as well. And it doesn’t have to start at the gym or the grocery store: it can start in our own heads.

Obesity is usually the product of a number of behaviors; consequently, to overcome obesity, we have to change the behaviors that caused obesity to begin with. That typically starts by changing our eating behaviors.

It isn’t food alone that contributes to obesity — it’s the type, the quantity and the frequency of the food that we must first examine. Realize that a diet, strictly defined, is simply the food that you eat. We have the notion that a “diet” is a short-term plan we’ll follow — like the “keto” diet or the “raw” diet — but short-term diets only deliver short-term results. When we go back to eating how we usually eat, the weight returns.

Instead, we have to reevaluate our entire relationship with food. What drives us to make the nutritional choices we make? What can motivate us to make better choices? How do we define or recognize satiety? Are there things that “trigger” us to overindulge or make bad nutritional choices? Are our eating habits a product of how we were raised? Were we scolded to clean our plates at every meal or frequently reminded of the stereotypical “starving children in Africa?”

Your primary care medical provider can discuss with you the dietary changes you need to begin losing weight and can work with you to develop strategies for changing your level of physical activity, ensuring you’re healthy enough to begin exercising and helping you progress toward a better level of fitness. He or she may recommend exploring these issues in more depth with the help of a therapist, counselor or even a dietitian who can help you recognize the cues that trigger unhealthy eating. This may mean changing your environment, such as cleansing your house and workspace of unhealthy food, removing stressful triggers and enlisting others to help hold you accountable. It may also mean setting measurable, realistic goals, keeping track of your food intake and physical activity, and even finding things beyond food that make you happy or bring you pleasure.

Remember, weight problems rarely develop overnight — they come from behavior patterns that lead us to consume more calories than we burn. While some short-term diets may help you lose a small percentage of weight, achieving and maintaining weight loss over a long period of time takes a firm commitment to ourselves and our health.