Multiple studies have shown that obese people have different intestinal bacteria than slim people, and the functioning of this gut microflora can impact your waistline.

After all, inside your gut is a living ecosystem, full of both good and bad bacteria. The functioning of this gut microflora in your body can be likened to that of an ant farm, working together as an intelligent whole to perform an array of functions, which include extracting calories from the foods you eat.  

One reason the microflora in your gut could play a key role in obesity is because it appears the microbes flourishing in an overweight body are much more efficient at extracting calories from food.

In fact, one study showed a family of bacteria known as firmicutes was more plentiful in obese people (20 percent more), whereas another bacteria called bacteroidetes was almost 90 percent lower.

Firmicutes appear to be more efficient at taking calories out of complex sugars and depositing those calories in fat. When these microbes were transplanted into normal-weight mice, they suddenly gained twice as much fat. And in a human study, obese people who lost weight increased their bacteroidetes, while the numbers of firmicutes decreased.

Another way your gut bacteria influences your weight is through a single molecule in your intestinal wall, which is activated by the waste products from gut bacteria. When activated, the molecule slows the movement of food through your intestine, allowing you to absorb more nutrients and thus gain weight.

Nearly everyone can benefit from optimizing the balance of good vs. bad bacteria in their gut using probiotics, but if you are pregnant or planning to be, this is of utmost importance to you and your new baby.

As this new study showed, simply taking a high-quality probiotic may help you to regain your figure after pregnancy, but the benefits go well beyond this. Research shows giving pregnant women and newborns doses of good bacteria can:

• Protect babies from developing eczema in childhood
• Help prevent childhood allergies by training infants' immune systems to resist allergic reactions
• Help optimize your baby’s weight later in life
• Improve the symptoms of colic, decreasing average crying times by about 75 percent
• Reduce your risk of premature labor

Babies that are given the best start nutritionally by being breastfed (the source of your first immune-building good bacteria) also tend to have intestinal microflora in which beneficial bifidobacteria predominate over potentially harmful bacteria.

So aside from taking probiotics during pregnancy, the first way you can encourage your newborn’s gut health to flourish is by breastfeeding.

Positively influencing the bacteria growing in your body is relatively easy, and involves taking in plenty of good bacteria while discouraging the growth of bad varieties.

One of the most important steps you can take to do this is to stop consuming sugary foods. Eating a healthy diet low in sugars, grains and processed foods will generally cause the good bacteria in your gut to flourish, and naturally build up a major defense against excessive amounts of bad bacteria that can damage your health.  

But even with an extremely low-sugar diet there are other factors that negatively influence your gut bacteria, including:

• Antibiotics
• Chlorinated water
• Antibacterial soap
• Agricultural chemicals
• Pollution

All of these factors help to kill off your good bacteria. This is why it’s a wise choice to “reseed” your body with good bacteria from time to time by taking a high-quality probiotic supplement or eating properly fermented foods like natto and kefir -- which are naturally rich in good bacteria.

Since helpful bacteria are increasingly absent in most people’s diets, it is important to purposely include fermented foods that contain live probiotic bacteria in your diet, or take a probiotic supplement regularly.