Because of a study where the ovaries of female lab rats were taken out, I’ve taken on a new battle cry: “Lose some weight. Get in shape. Save the world.”

Researchers at the University of California Riverside did this to gain insight into why men and women accumulate body fat differently, and it worked. Djurdjica Coss, the leader of the study, told Medical News Today that the removal of the ovaries ascertained “that ovarian hormones are indeed protective against weight gain.”

Helpful info for sure, but it was a bit background information Coss provided that created my new battle cry. “Obese men,” she said, “have lower testosterone levels, contributing to low libido, low energy, and reduced muscle strength. We see this in mice, too; obese male mice showed nearly 50 decreases in testosterone and sperm number.”

Similarly, she adds: “Obese women . . . don’t ovulate. Obese female mice show the same, contributing to decreased fertility.”

So can you see how my fertile imagination took me well into the future? If humans keep getting heavier and heavier, the birth rate should dip lower and lower and ....

If the obesity epidemic is unabated, it’s theoretically possible that in a few thousand years the human race will die out — not from nuclear war, global warming, or famine — but because our big fat bodies won’t be able to produce babies.

Far-fetched? For sure. But this very remote possibility establishes a very important point. Obesity has to be really debilitating if it reduces the birth rate at all.

But it’s more than debilitating. It’s insidious. At least, initially. An extra pound one month goes unnoticed. So do the two gained the next.

And then, maybe two years later, you see yourself in a mirror and think, “My god, what have I done?”

It’s hoped that the following info can help keep you from ever looking at a mirror and asking that question.

After all, you can’t save the world if you’re part of why it needs saving.

Fortunately, if you’re trying to save yourself by losing weight, you don’t have to lose that much to help your health.

In fact, when researchers examined the results of the most recent National Health and Nutrition Examination Survey created from 7,670 individual ones filled out by American adults, 62 percent of participants who had dieted to lose weight had been unable to reach their goal weight.

But that didn’t mean their efforts were for naught.

The researchers ascertained that those who had still been able to lose 5 to 10 percent of their body weight — as little as 12 pounds for a beefy 240-pounder — were 22 percent less likely to develop metabolic syndrome.

Now that may not sound so impressive since metabolic syndrome is a confusing, catch-all term. Just remember that you certainly don’t want to “catch” any of the diseases that metabolic syndrome promotes, such as heart disease, diabetes, and stroke.

But also remember that the more weight you can lose — especially when you need to lose a lot — the better. The participants who lost over 20 percent of their body were nearly 2.5 times less to develop metabolic syndrome than the 5-to-10 percenters.

If you’ve somehow managed to keep a healthy weight without working out very infrequently or at all, consider what Dr. Stuart Phillips, a McMaster University professor in kinesiology, recently shared during an interview with Global News: “The [physically] stronger you are, the more resilient you are against disease and overall risk for mortality.”

Moreover, any type of exercise reduces the likelihood of contracting “all the classic chronic diseases,” such as heart disease, cancer, and type 2 diabetes.

And if increasing strength is your goal, you need to do one specific type of exercise at least once, preferably twice, and optimally three times a week. Weight lifting.

While many think increasing the time and intensity of cardiovascular workouts is the best way to lose weight, weight lifting may very well be even more effective over the long term — and is definitely a better way to increase strength.

Yet what may be the best reason to lift weights is its ability to — in one important way — offset the law of diminishing returns.

If you begin running, build up to a three-times-a-week, three-miles-a-run regimen, your body acclimates to it in a few weeks, learns ways to become more efficient in its movements, and therefore the run requires fewer calories to fuel at the six-week mark than when you started.

This, in a nutshell, is the law of diminishing returns.

But progressive weight lifting adds muscle. Muscle needs calories to sustain itself. Therefore, even if you acclimate to the movements in six weeks and add no additional muscle, the already added muscle still requires calories.

That means you can eat more than before you started without adding body fat.