Antibiotic overuse during childhood is rampant. Most physicians, often at the parent’s urging, will prescribe an antibiotic for colds, flu, and ear infections even though antibiotic prescription is not indicated in such cases. Antibiotics are unnecessary for these common childhood ailments, and their overuse has far-reaching negative effects.

In a recent study published in the Journal of the American Medical Association (JAMA) Pediatrics, researchers studied the medical records of almost 65,000 babies and children in the Philadelphia area. They discovered that babies who received wide-spectrum antibiotics (including amoxicillin, tetracycline, streptomycin, moxifloxacin, and ciprofloxacin) during their first two years of life were 11 percent more likely to be obese between ages 2 and 5 than those who did not receive the drugs. And the earlier the exposure to the drugs, the more likely the child was to be obese between age 3 and 5.

“Because the first 24 months of life comprise major shifts in diet, growth, and the establishment of intestinal microbiome, this interval may comprise a window of particular susceptibility to antibiotic effects,” noted the researchers.

Martin Blaser, a prominent researcher who is currently studying the effects of antibiotics on the human gut microbiome has said, “Antibiotic perturbation may cause a shift to an alternative stable state, the full consequences of which remain unknown.” His studies have found that gut bacteria may never fully recover after antibiotic use.

Antibiotic use has been linked to obesity in adults and children in previous studies, so this new study in children only adds to the evidence that gut bacterial balance is essential for weight management. Truly there is more to the story than calories in, calories out, a topic that I cover in depth in my new book, The Skinny Gut Diet.

“This really gives strong evidence that, often, obesity really is not a personal choice,” noted Stephen Cook, MD, MPH, lead researcher. He said that childhood obesity “is a much more complicated issue than ‘move more and eat less.’”

Even the authors of the study are skeptical that physicians will give up using antibiotics for these conditions, so they suggest using narrow-spectrum antibiotics instead, which target a smaller group of bacteria and have less of a negative impact on the beneficial gut bacteria. This is a step in the right direction, but judicious use of antibiotics is really imperative if we are to stop the spread of antibiotic resistance.