Antibiotics Weight Gain | What You Need To Know - Natren, Inc.

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Antibiotics Weight Gain

If you’re prescribed antibiotics, it’s likely because you have an infection that the medicine can treat. While antibiotics are one of the most important medical innovations of all time, and have saved countless lives, there are also drawbacks to them. If you’ve taken antibiotics, you’ve probably experienced the stomach cramps and diarrhea that are frequent side effects. A common question people ask is whether antibiotics can cause weight gain. There are studies that indicate antibiotics ability to play a role in weight gain, potentially both while you take them and after. Here’s what we know about antibiotics and weight gain. 

How Antibiotics Increase Hunger

One way that antibiotics may lead to weight gain is because of a hormone called ghrelin. Ghrelin is sometimes called ‘the hunger hormone’ and it’s incredibly powerful. Have you ever seen a TV commercial with a plate of hot, crisp, french fries, and felt a wave of hunger wash over you? That’s not your imagination - it’s ghrelin. Even seeing a picture of tempting food can spur our bodies to produce more ghrelin, and this hormone makes you feel hungry. It’s no surprise that by increasing the ghrelin in your body, you’re more likely to overeat. Some research shows antibiotics may play a role in increasing ghrelin. 

A particularly interesting study looked at a group of Veterans who were given antibiotics to get rid of a strain of bad bacteria known as H. Pylori. While the antibiotics were successful at getting rid of the bad bacteria in almost all the cases, the inevitable happened: the antibiotics also wiped out good bacteria. It’s important to understand that antibiotics are not “smart”. They cannot distinguish good bacteria from bad, so when you take these medications, you will also wipe out many of the healthy bacteria in your gut. 

When scientists looked at the aftermath of the Veterans who took the antibiotics, they saw substantial increases in their ghrelin levels. Along with this, they saw weight gain. Notably, the researchers said that before the study, BMIs were constant. Additionally, the study group that did NOT take antibiotics also saw their BMIs stay consistent. However, the group that took the antibiotics and wiped out the H. Pylori bacteria (as well as many good bacteria), overall saw “BMI progressively and significantly increased, reaching 105 ± 2% by 18 months of follow-up… The change in BMI relative to baseline also was significantly greater at 3, 6, and 12 months following eradication” of the bacteria as well. 

This last statement is especially important because it indicates not only a change during the short course of antibiotics that most people take, but significant changes in BMI even 12 months following the course of antibiotics. 

How Antibiotics Disrupt the Digestive System

The foundation of much of your digestion is the bacteria in your intestines. Good bacteria helps break down food into usable pieces, and allows the body to benefit from protein, carbohydrates, dairy, and other nutrients. Even if you eat the most healthy diet you can imagine, you may not truly be benefiting from that food if your body cannot digest it properly. Antibiotics kill good bacteria, and these good bacteria are essential to an optimized digestive system. While you may be taking your antibiotics for two weeks, the effects of the drugs can be substantially longer. Sometimes people assume that a few days without antibiotics will give their digestive system a chance to recover. However, there is research showing that people can go six months and not see a recovery of the good bacteria they need. Without an optimized digestive system, it’s easy to see how antibiotics can lead to weight gain. 

The next question is: when you take antibiotics, is weight gain inevitable? The answer is no. You can take a substantial step in ‘undoing’ the negative effects of antibiotics by taking a high quality probiotic. 

Probiotics and Antibiotics - Why They’re a Good Match

In some ways, probiotics and antibiotics are opposites. Probiotics put bacteria in your body and antibiotics kill bacteria. So how would it make sense to take them both? The answer to this lies in remembering that antibiotics are not smart enough to only kill the bad bacteria. So when you take an antibiotic, and it kills both good and bad bacteria, probiotics are able to come in and replenish the good bacteria that you need. 

It’s important to make sure you take probiotics and antibiotics at least 2 hours apart. When taken correctly, precision probiotics can counteract some of the negative side effects of antibiotics. They can put good bacteria right back into your digestive system where it’s needed. This good bacteria can then do its job by supporting strong immunity, optimized digestion, and even healthy weight. 

What Probiotics are Best with Antibiotics?

There are so many probiotics you can choose from, and so few that truly deliver on what they promise. Because of the amount of money some companies spend on marketing, thousands of well-meaning consumers throw money away on probiotics that prioritize sales over science. When you’re looking for a probiotic to balance out some of the damage that antibiotics can do, it is essential that you’re getting the highest quality. This is where Natren comes in. All of Natren’s probiotics are manufactured with standards far beyond the minimum required. They all come with a 100% potency guarantee of each strain of healthy bacteria in each supplement. Additionally, they were developed by a founder and her team with almost 40 years of experience as leaders in the probiotic industry. 

While there are quite a few probiotic supplements to choose from at Natren, we recommend that probiotic newbies start with Healthy Trinity. When you’re worried about side effects of antibiotics - both during your treatment and long after - Healthy Trinity gives you an easy way to take 3 different Natren products, all of which are designed to optimize your digestive system. Children, adults, and seniors can all benefit from Healthy Trinity, and it can be taken both during antibiotics and after. 

We highly recommend you start a probiotic routine as soon as possible. If you’re taking antibiotics, there’s no need to wait until your medicine is done (although it’s always best to consult with a doctor about any medical questions). Taking a Natren probiotic can put you on the road to restoring healthy digestion from day 1 of your treatment. We recommend taking Natren probiotics two hours after each antibiotic dose. Please visit us at for more information about the best probiotics you can take, or to learn more about our high standards and expertise. 


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