America, you're fat. Here are 3 reasons why and what can we do to lose weight

Obese man's waist
Obese man's waist

There is no delicate way to put it. Americans are fat and getting fatter every year.

Currently, 38% of men and 41% of women are obese, numbers that have doubled over the past three decades, and worse, the number of fat children and teens has tripled. But, why are we so fat?

The simple explanation is that we eat more calories than we burn each day, leading to an excess of calories in the body that are converted to fat and stored.

An argument can be made that this is not entirely our fault as we have fallen victim to lifestyle trends that sneaked up on us, and this is especially true for our children. For example, consider the role of our school systems. Kids expend fewer calories each day because of a reduction in physical education classes and recess, and less participation in organized sports. In addition, to boost revenue, many school systems have contracts with soft drink and fast-food companies, encouraging unhealthy and fat-promoting eating practices at school.

Add to all this the fact that at home, kids are playing video games or engaging in social media, instead of going outside to play. And, of course, adults move less as well, with space-age appliances, multiple car families, and too much TV, plus working more to pay for the high cost of living.

You may likeVitamin D2 vs. D3? Are artificial sweeteners bad? Readers' health questions answered

How has the fast food industry contributed to obesity?

Other behind-the-scenes trends have been operating as well, including high fructose corn syrup resulting in more calorically dense soft drinks, snacks and convenience foods. The fast-food industry also was hard at work contributing to American fatness. First was the introduction of "value meals," which combined sugary soft drinks with high-fat French fries and burgers. Soft drinks cause a big insulin response while fries and burgers provide lots of dietary fat calories. Insulin not only regulates blood sugar, but it also promotes the conversion of excess calories into body fat.

Another problem with fast food was the introduction of "supersizing" as the portion of French fries was greatly increased, tripling the number of calories per serving.

At the same time, busy Americans had less time to cook wholesome meals at home, and the frequency of eating out doubled in recent years. Eating out typically results in eating more than you do at home. Not only is volume increased, but restaurants need to appeal to our taste buds to draw us in, which means more emphasis on fat and sugar.

So, what can we do about it?

Why do people tend to overeat?

The economics of eating in America make it easy to overeat high-calorie foods.
The economics of eating in America make it easy to overeat high-calorie foods.

The American lifestyle combined with our genetic inheritance is the perfect storm when it comes to promoting body fatness. Genetically, we are programmed to survive, and in order to survive, we must have an ongoing supply of energy. No problem, right?

Certainly not in today's society with a fast-food restaurant on every corner.  Unfortunately, our genes don't take into account our current ready availability of food. On the contrary, we evolved from early man when eating was unpredictable, and that fact combined with our drive to survive has shaped our behavior in a number of ways, starting with hunger, our strongest drive.

If we are denied food for a prolonged period, the hunger drive is so strong we will do almost anything to assuage it. For example, early man had to be driven hard by hunger every day to put forth the extreme effort required to procure food to feed a family. Now, fast forward to today and imagine being hungry and walking into a fast-food restaurant. Compared to early man, there's no effort involved in getting food, plus there are no limits. As a result, we regularly overeat far more than the body needs.

You may likeWhat is high-fructose corn syrup and why is it bad for you? Here are 4 things to know

Worse, it feels natural, and it is.

Whether organic or non-organic, be sure to eat those fruits and veggies.
Whether organic or non-organic, be sure to eat those fruits and veggies.

When our ancestors selected foods to eat, their choices were limited.  If they ate meat, it was wild game, lean and tough and low in fat and calories. The things they could gather or grow, nuts, roots, fruits and vegetables, also were very low in calories. That means they had to eat a lot in order to take in enough energy to survive. This combined with the strong hunger drive and the unreliability of food, caused them to eat as much as possible any time they had the chance.

Fast forward to today, and it's no wonder we find ourselves eating large portions and seeking out “all-you-can-eat” restaurants. In fact, lack of portion control is a huge factor in obesity, especially with high-calorie foods. Sound familiar?

Sure, because it feels natural, and it is.

How does the human body store fat?

When we consume too many calories, our bodies are programmed to take the excess energy and store it in the form of body fat. This, too, makes sense to the body, because carrying around a bunch of extra stored energy in the form of fat takes some of the pressure off needing to consistently find and consume calories in order to survive. If you can't eat for a while, a common occurrence for our ancestors, you can simply tap into the energy you have stored as fat.

This is why your body loves every ounce of fat you have on you, and it always wants more, because more fat means more energy and more energy boosts the odds of survival ― or, at least it did way back then. Today all this excess fat is killing us, and the fact that our body loves fat helps explains why it is so reluctant to shed fat and keep it off.

You may likeWhy diet soda is bad for you and not the answer if you're looking for quick weight loss

The bottom line is the deck is stacked against us when it comes to weight management. Our lifestyle combined with our genetic programming conspire to make us fat. Ironically, it all feels quite natural, and it is. This doesn’t mean it’s impossible to buck the odds. Not at all. But it takes considerable dedication and effort, plus you cannot let your guard down.

Let me add that the worst mistake you can make is to allow yourself to gain body fat with the thought that you will take it off later. It’s much easier to prevent gaining fat than it is to lose it.

Reach Bryant Stamford, a professor of kinesiology and integrative physiology at Hanover College, at stamford@hanover.edu.

This article originally appeared on Louisville Courier Journal: 3 reasons we're fat and how to change your diet to lose weight