Antibiotics — Making Us Fatter?

Our gut bacteria are gaining more and more press nowadays — assisting our immune functions, taking hand in nutrient absorption, and even warding off cancer. But, most recently, our imbalanced microbiomes are being blamed for making us… fatter.

Why are our microbiomes so imbalanced? One culprit is antibiotics. Often overprescribed, antibiotics are bacteria killers, demolishing all of the bacteria in our guts indiscriminately. However, some colonies of bacteria in our guts are good — even essential. They are indispensable components of our digestive, immune, and regulatory systems. They even help fight off disease — and our incessant use of antibiotics (especially early in life) is killing them. So right off the bat, antibiotics have made our microbiomes far less healthy and diverse.

But are antibiotics making us fatter? Since our gut bacteria are so involved in bodily functions and weight maintenance, any disruptions of their fragile balance could be responsible for our increased girths. Simply look to factory farming. For decades, industry farmers have laden their animals’ food with antibiotic powder, as it allowed them to survive in cheaper, more squalid conditions while making them grow much, much larger.

The average American is an inch taller and 24 pounds heavier than 50 years ago. A third of our population is obese. While diet plays a large role in our weight gain, the strange concoction of hormones, chemicals, and antibiotics we encounter in our daily lives are also to blame. In one study, mice fed antibiotics and a heavily caloric diet, like the diets of most Americans, led to mice gaining almost twice more weight than the control group. In another study, it was shown that children who were overweight by age 3 were more likely to have been prescribed antibiotics within the first 6 months of their lives. 

It would seem that, contrary to past belief, there is such a thing as too many antibiotics. Although scientists aren’t exactly sure of the precise mechanisms that lead to antibiotic-induced weight gain, they vastly depopulate our microbiomes and open up the opportunity for less benign bacteria to take the helm. We certainly need antibiotics — there is no doubt there. They have done a lot of good in their history. But now they are being abused — overprescribed, especially to children. It would be prudent for us to limit our dependence on them, lest we wish to create antibiotic-resistant superbugs or perpetuate the issue of obesity.

Of course, antibiotics aren’t solely to blame for our skyrocketing rates of obesity. Diet, marketing schemes, preservatives, pesticides, and chemicals all take a hand in this grand fattening experiment that is our food system. Use your sense — cut out antibiotic-laced foods — eat local and natural, and keep your body close to nature.