Can Antibiotics Cause Weight Gain

author avatar Dr. Eric Berg 08/31/2023

Weight gain and obesity are common problems in the US today. There are many reasons for this. Some are more obvious, like those related to unhealthy diets and eating patterns. But some are less obvious. For example, did you know that there is a link between antibiotics and weight gain?

Antibiotic treatment is very common in the medical world. Most of us have been prescribed one by our doctors for a bacterial infection. And antibiotics are also used in factory farming, so they can get in our food, too.

But can they really cause you to put on weight and gain some extra pounds? The answer is yes.

In this article I will cover:

Pills arranged to spell the word antibiotics on a black background | Antibiotics and Weight Gain

The problem with antibiotics

This kind of medicine is used to kill bacteria when we have an infection. This is a great thing when we have a serious infection and are really sick.

The problem is that antibiotics kill all of the bacteria in our bodies. They don't just kill the bad ones we are trying to get rid of. They also kill the good, friendly kind.

We have a thousand trillion microbes growing around and inside of our bodies. Some of these are unfriendly. Those are the ones that cause problems when they grow out of control. They can result in infection and illness. But other microbes are good and helpful. They are needed for the body to function properly.

So when antibiotic exposure comes into play, the balance of helpful to harmful microbes is completely thrown off.

There are two main ways that we experience antibiotic exposure.

  1. When we are prescribed these drugs from our doctors to treat an infection.
  2. When we eat foods that aren't grown naturally.

Most of us know about the ones we get from our doctors, but let's talk a little bit more about the ones in our food.

Antibiotics in the diet

When we eat commercially produced animal products like meat and dairy, we are actually exposed to a lot of antibiotics.

The unhealthy conditions animals are living in on big-scale farms are a breeding ground for sickness. So farmers inject these medicines into the animals as a precaution to prevent infection.

Some of that medicine stays in the meats and animal products that we eat. And some of it is excreted from the farm animals. That manure can then be used to grow the fruits and veggies that end up in our kitchens and on our plates

So if you aren't eating organic, clean foods? Then you are getting antibiotic exposure through many of the foods that you eat.

And that can mess with the bacterial balance in your body.


Why you need to make friends with your flora

As I said before, we have both helpful and harmful microbes in our body. The bacteria that inhabit our bodies (largely in our gut) are called the microbiome. Keeping the microbiome balanced is key to your overall health and wellness.

But why is our gut flora so important?

The good bacteria in your body do so much to keep you healthy. Friendly bacteria like lactic acid bacteria do things like:

  • Protect you from toxic microbes.
  • Boost your immune system.
  • Make the vitamins your body needs to stay healthy.
  • Enhance the nutritional value of your food.
  • Cleanse the blood.
  • Act as a colon cleanser.
  • Keep the pH balanced in your gut.

Learn more about why we need friendly flora in this video.

In order to really experience great health, we need to start seeing our flora as partners in our health.

If we don't keep our gut flora happy, then lots of problems can start to arise in the body. One of those problems?

Gaining weight.

The link between antibiotics and weight gain

Our gut flora plays a key role when it comes to gaining weight. The gut microbiome impacts the foods you crave and your hunger levels, for example. So antibiotic use poses a major problem.

When antibiotics are used in the body, we can quickly get an increase in bad bacteria. Good bacteria help to neutralize the bad and keep them in check. So when the good are killed off, an overgrowth of bad can occur.

Bad bacteria produce things that increase cravings, hunger, and inflammation in the body.

When that happens, it can quickly lead to Fat Storing Hormone resistance. And Fat Storing Hormone resistance causes weight gain.

This is how it works:

Antibiotics → Overgrowth of bad bacteria → Cravings, hunger, inflammation → Fat Storing Hormone resistance → Weight gain.

Fat Storing Hormone resistance is often caused by our diet. Mainly, this means eating too much sugar or eating too frequently. But it can also be caused by an imbalanced microbiome.

So when it comes to antibiotics, what causes you to gain weight, get fat, and maybe even lean towards obesity? Fat Storing Hormone resistance occurs as a result of bacterial imbalance.

Researchers have studied the link between gut microbiota, unhealthy weight, and obesity. More and more, we are seeing that microbiota can impact body weight. And that antibiotic use can be linked to weight issues.


What can you do to avoid this problem?

It is important to prevent the harmful link between antibiotic use and weight gain. Here are the top tips you can follow to keep your gut flora healthy and your weight in check as a result.

1. Eat animal products that are free from antibiotics.

Organic, grass-fed meats and dairy are your best bets. Lower your intake of commercially processed animal products, and increase your intake of organic ones instead. This will help your body in so many ways, especially when it comes to antibiotic exposure.

Overweight man holds a blue measuring tape around his belly fat | Antibiotics and Weight Gain

2. Be cautious with antibiotic use.

Don't always jump to antibiotics for your first line of treatment. This doesn't mean that you never need them. Sometimes they are necessary and life-saving. But always ask your doctor if they are the only option. Not all infections need antibiotic treatment. You may be able to try fighting the infection on your own, first.

3. Feed your flora well.

Remember that you want to become friends with your flora. This means doing what you can to keep your gut health happy and balanced. Choose to eat foods your good flora need to flourish. Increase your intake of veggies that are high in fiber. Fermented vegetables are the microbiome's favorite kind of food, so try those. Eat things like sauerkraut, kimchi, and more.

The bottom line

Antibiotics can definitely cause you to gain weight. This is true whether you take them as medication or are exposed to them through your diet.

They kill off all your friendly bacteria that help keep your body in balance. When the bad bacteria start to take over, your cravings, hunger, and inflammation get out of whack. This ultimately results in Fat Storing Hormone resistance and then weight gain.

To avoid heading towards excessive weight gain or obesity, keeping your intestinal bacteria happy is key. This means watching your antibiotic exposure.

So if you want to avoid putting on some extra pounds, here is what you can do:

  • Avoid antibiotic-filled animal products. Choose organic, grass-fed meat and dairy.
  • Limit antibiotic use when you can. Talk to your doctor about your options before taking a prescription.
  • Feed your friendly gut bacteria. Opt for high-fiber vegetables and fermented foods.

Did you know that you could gain weight because of antibiotic use? What are your thoughts? Share in the comments section below.


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