Americans gained over 500 million pounds last year

Weight Watchers reports earnings Thursday, and even if the numbers aren't good, there's one figure that should make investors in dieting hopeful: 582 million.

That's how many pounds Americans gained collectively in 2015. Through births, immigration and overeating, there has been the equivalent of 1,400 blue whales added to the human biomass of our country in just a year, pointing to the need for groups like Weight Watchers to get the country lean and mean again.

Figures from the U.S. Census Bureau and weight data collected by Gallup tell the story.

The average American man weighed 196 pounds in November, according to Gallup, up 3 pounds from a year earlier. The average woman actually lost 2 pounds since 2014 and weighed 155 pounds. With 322 million people in the country and accounting for the gender ratio, that works out to a total human biomass of around 56.5 billion pounds.

That's 1 percent more than the previous year and the biggest collective gain since 2011.

Based on the standard of 3,500 calories per pound, more than 2 trillion calories were added in 2015. That's enough energy to power all of New York City for 14 days.

But don't go throwing out your solar panels or disconnecting from the grid: That's just based on back-of-the envelope calculations. A number of people have disputed the 3,500 calories-per-pound ratio as a simplistic way to look at weight loss, and it probably is.

But it's an interesting way to look at a serious problem in public health and put it in a fresh context.

The issue of excessive biomass in a population is an important one. Research has shown that increasing population weight can have the same effect on the world's food energy as adding an extra half-billion people to the planet.

Yes, the total weight gain of 582 million pounds includes more than just obesity. It also takes into account new babies, children growing up and new immigrants to the U.S.

And before you tweet this article to Donald Trump as evidence that we should deport more recent immigrants to get the collective weight down, keep in mind that the obesity rate among Americans reached an all-time high in 2015 to 28 percent.

A full 42 percent of men report that they weigh more than 200 pounds, up from 36 percent in 2014. That's the biggest percentage-point change in either gender by weight group.

We may be getting heavier, but we are interested in reversing the trend. At least once a year.

The chart above shows Google search traffic for the terms "diet" and "gym" over the past decade. The biggest spikes are around new years, when we spend time making New Year's resolutions about getting more exercise and eating less. Then, as the year goes on, we ditch all that.