Do Antibiotics Make You Gain Weight?

Written by:

Obi Obadike

Obi Obadike

Celebrity Fitness & Nutrition Expert, CFT, SFN, M.S. Founder & CEO – Ethical Inc.
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Do antibiotics make you gain weight? There was a study done in mice that a change in their gut microbiota was caused by antibiotic use and the result was more fat accumulation. For many decades it was known that if you inject farm animals with antibiotics you can fatten them up. They tend to gain weight quickly when treated with antibiotics.

An antibiotic treatment should be only used if a doctor medically advises you to take it to alleviate major infection. But if you are just taking an antibiotic just because you felt you had taken one based on your own self diagnosis then that is not the smartest health decision to make for yourself.

Misuse of antibiotics is not necessary for minor non bacteria illnesses such as colds and flus. It should only be used for serious bacterial infections. It is meant to save lives not meant for small sniffles, sneezes, or coughs.

Do antibiotics make you gain weight? Photo credit: iStock-Bet_Noire

Here are some of the dangers of taking an antibiotic if you don’t need to.

  • Poor digestion and nutrient absorption
  • Symptoms of gastrointestinal disorders such as IBS, gas, constipation, diarrhea, etc.
  • Potential growth and spread of harmful pathogenic bacteria.
  • Imbalance of healthy gut bacteria.

There are research studies that show that gut imbalances can contribute to someone becoming overweight or making it difficult for someone to lose weight. The more imbalance of bacteria in your gut the higher the degree of difficulty it is for weight loss.

There was a British study that was done on children that found that antibiotics treated at an early age are more likely to become overweight or obese as adults. Another research study review on JAMA showed that kids who treated four or more courses of antibiotics before they were two years old ended up with a 10% higher risk of obesity.

Anything that you eat is processed by your gut and if your gut is working efficiently it will negatively affect how you burn calories effectively. There are research studies that show that taking one course of antibiotics can negatively affect your gut bacteria for one year.

So that is essentially a year of bad bacteria to grow and mess with your good bacteria while affecting your digestion and metabolic system.  And this is one of the main reasons why you should only take antibiotics for serious bacteria issues.

“For many decades it was known that if you inject farm animals with antibiotics you can fatten them up. They tend to gain weight quickly when treated with antibiotics.” Celebrity Fitness & Nutrition Expert Obi Obadike

The Bottom Line there are research studies that show that animals can gain weight when given antibiotics. There are also studies that show that children who overuse antibiotics have a 10% increased risk of being overweight or obese.

The negative thing about antibiotics is it can disrupt your gut health with bad bacteria which would make it difficult for you to burn calories effectively. You should only use an antibiotic for serious bacteria illnesses prescribed by a doctor.

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  3. Turta O, Rautava S. Antibiotics, obesity and the link to microbes – what are we doing to our children? BMC Med. 2016 Apr 19;14:57. doi: 10.1186/s12916-016-0605-7. PMID: 27090219; PMCID: PMC4836077.
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