The Truth About Bacteria And Weight Loss

By Kevin DiDonato MS, CSCS, CES

You made it through the holiday season.  And now you are moving along through January.  You may be busting your butt at the gym along with a TON of other people.  You are curling your dumbbells when the person next to you suddenly sneezes, releasing possibly dangerous bacteria.  Uh-oh, now you remember another reason why you DISLIKE New Year’s.  


Not only are you in the middle of New Year’s resolution time, but you are also in the middle of cold and flu season.  You think to yourself that this is no time to get sick.  But it may be too late.  You feel the familiar scratchy feeling in your throat, or your nose just got stuffier.  So you run to your doctor to stop your cold…DEAD.  You ask for some antibiotics.  But you may have made a very poor choice…

Antibiotic Use
During cold and flu season, it may seem like doctors are very quick to prescribe antibiotics.  And you may jump at the opportunity even if you have the common cold (which usually is a virus).  Thinking that antibiotics may help (which more than likely they won’t) to cure your cold before it explodes into something bigger.
But the problem is this: antibiotics DESTROY bacteria, NOT viruses.
Don’t get me wrong, antibiotics may have saved us from some very terrible diseases.  Diseases that killed thousands, if not MILLIONS, of people!  So if you are suffering a severe bacterial infection or a life threatening situation calling for antibiotics, then you NEED them.  But for your common cold or flu, the use of antibiotics may be the WORST thing you want to do.  

Especially if you want to LOSE FAT, Wait…what’s that, antibiotics may lead to WEIGHT GAIN?

Let me explain…

Inside Your Body, Inside each and every one of us lives certain “good” bacteria.  And these friendly bacteria may help your immune system.  This may keep you healthy from other invading “bad” bacteria.
Plus, these “good guys” may regulate certain hormones responsible for weight loss or gain.  They may help DIGEST FAT, breaking it down into smaller absorbable nutrients.  But how exactly do antibiotics lead to weight gain?  


Imagine you are a farmer.  And you want to sell your meat to the local grocery store.  But you are in competition with the next farmer over, who have MUCH LARGER and FULLER cows than you do.  So you start your cattle on antibiotics.  After a few weeks, you notice an increase in the weight of your cows, leading to BIGGER and MEATIER cows.

This happens almost every day, all across the country.  The antibiotics used in livestock may destroy healthy bacteria, which may result in bigger and fatter cows.  Plus, the meat you end up with is FATTIER instead of leaner.  So the meat you eat is fattier and possibly full of hormones and ANTIBIOTICS.

So if that happens in cows, do you think it might translate in humans?  My guess is you might be right!

Antibiotics and Weight Gain.  Your fat tissue releases hormones which may regulate your energy status.
One hormone communicates with your brain, letting it know your energy needs have been met.  But the other hormone also talks to your brain.  It tells your brain when your energy is low and you need to EAT.

This may increase Ghrelin secretion, which then tells your brain that you need to EAT MORE.

And this may reduce your concentration of Leptin, or your body may become resistant  to Leptin and its signaling.  This may cause you to overeat and possibly storing it as fat.  Your intestines also have certain receptor sites which bind to the tails of those bacteria.  This may stimulate metabolism of certain nutrients.

And this may increase your blood sugar.  Then, your pancreas secretes insulin to shuttle that sugar into your muscles to be used for energy.  The problem is: When there is an unhealthy gut environment (too many bad bacteria and not enough good bacteria), there may be an increase in inflammation.

So then your body sends a response to deal with the inflammation.

As a review, when your cells become inflamed, they may be more resistant to certain powerful hormones resulting in reduced cell signaling.  And this is especially true with insulin.  When your body becomes resistant to insulin, your chances of developing metabolic syndrome increases.

Metabolic syndrome may be associated with high blood pressure, high cholesterol, and
increased risk for developing diabetes or heart disease.

By altering your gut bacteria, you may alter your body’s ability to control inflammation and your sensitivity to insulin.  But it does not stop there…  A study conducted on mice deficient in TLR5, which is a protein located on your intestinal wall, produced some AMAZING results.

These genetically altered mice exhibited classic signs of metabolic syndrome.
They showed insulin resistance and inflammation.
And they exhibited altered gut microflora.
When the gut microflora were transferred to mice lacking an immune system (that way the mice would not fight off the bacteria), the researchers noticed the mice ate more.
This resulted in increased body weight gain and eventually led to metabolic syndrome.

Good Germs,  Bad Germs.  Antibiotics are powerful drugs which may rid your body of good and bad bacteria.  By altering your gut microflora, your appetite may increase.  This increase may raise your chances of weight gain, especially FAT GAIN.  Farmers have used antibiotics for many years to increase the size to make fatter and bigger cows with more meat.  This use of antibiotics may also destroy a certain bacteria which may be on the brink of extinction.  This bacteria may aid in digestion, and without this bacteria, ghrelin secretion may INCREASE possibly increasing your appetite.

Hope is not lost though!  There may be a chance to replace your good bacteria after using antibiotics.  Probiotics are products that may contain healthy bacteria.  And these bacteria may help your normal gut bacteria flourish, possibly protecting your body from harmful bacteria.

So, next time someone sneezes by your side, reach for a tissue and wash your hands.  This may prevent you from having to use bacteria-killing antibiotics.

Your health and the health of the millions of tiny good bacteria may depend on it.


Did you know you can still exercise if you have just a head cold?  I can adjust an exercise program for you.