“Sixty years ago almost everyone was thin,” Alanna Collen explains in her book, “10% Human” (Harper, 2015). That could be why, as a little guy born at that time, it bothered me that I wasn’t.

I was fat and said as much to my mom.

She disagreed, telling me time and time again I was “only chubby.”

That ended on a back-to-school shopping excursion with her when I was 11 and asked, “If I’m not fat, then why are we in the Husky Boys’ section?” Her silence started a six-month stretch where I wore ankle weights everywhere I went and replaced school lunches with a walk home and a single eight-ounce serving of fruit-flavored yogurt.

I wrestled for the first time that winter, yet still played basketball in a league. In addition to practices and games, I also played for two hours twice a week when the township held an open gym as well as the occasional pick-up game after school.

By baseball season, I was 12 pounds lighter, two inches taller, and suddenly a base stealer.

I tell you this because, as Edward R. Murrow once said, “Everyone is a prisoner of his own experiences.” My preteen penitentiary has probably led me to pen this column - and pick many of the topics I pick.

That’s why I gambled last week and referenced a study about something as little known as metabolic adaptation. Little known or not, the findings support what I came to believe by the time I turned 12: People are not fated to be fat.

It can only help your health if you feel the same. So here’s more grist for the mill that also focuses on the little known: the effects of gut bacteria on weight loss.

Researchers at the Institute for Systems Biology in Seattle examined information they accrued from testing 105 individuals on a commercial behavioral wellness program where one of the goals was weight loss. Now you probably don’t want to know all the specifics about the testing and number crunching - or learn about functional profile or metagenomic analysis - but the study published on Sept. 14 in the journal mSystems makes one thing clear.

Every time your body digests carbohydrates and proteins the bacteria in your gut consume some - and it’s a telling amount.

In a Medical News Today article by Deep Shukla, for instance, Dr. Sean Gibbons, the study’s lead author, calls gut bacteria a “major player” in the game of weight loss. Gibbons and his colleagues “found gut microbiome genes associated with bacterial replication and the breakdown of carbohydrates and proteins predicted weight loss response.”

In other words, whether or not the commercial behavioral wellness program produced weight loss depended upon the types of bacteria in the guts of the 105 subjects.

Since the foods you choose help determine the makeup of the bacteria in your gut, that makes you a “major player” too.

This is evidenced in a study Alanna Collen cites in “10% Human” that compares the diets of children in a rural African village to those in an urban Italian city. While the village kids eat primarily a “‘savoury’ porridge dipped into a sauce of locally grown vegetables,” an occasional chicken, and, “for a tasty treat during the rainy season,” termites, the urban kids consume foods “common in a modern Western diet: pizzas, pasta, a lot of meats and cheeses, ice cream, soft drinks, breakfast cereals, crisps [what the Brits call potato chips] and so on.”

Because these diets are so radically different, so too are the bacteria in the children’s guts.

About 70 percent of the bacteria found in the village kids’ were “completely absent” from the urban kids’. And what bacteria did the urban kids have?

Mostly Firmicutes, which have been found to be prevalent in the guts of obese adults. What the village kids had instead were primarily Bacteroidetes, the bacteria found in high proportion in lean adults.

Another study cited by Collen, found obese mice had “more Firmicutes and fewer Bacteroidetes” than normal mice and that the difference led obese mice to absorb two percent more calories from their food.

Apply the difference to a woman who needs 2,000 calories a day to maintain her present weight and it “adds up.” In one year, according to Collen’s calculations, the woman gains just over 4 pounds - and just shy of 42 pounds in 10.

Now I do not expect you to search the internet for porridge recipes simply because you read this article, but you many want to eat more fiber.

Another study Collen cites shows when 250 American women did nothing else to their diets but increase fiber intake by 8 grams per 1,000 calories - thereby creating a better environment for “good” gut bacteria - they lost nearly 4.5 pounds in 20 months.