Weight is a sensitive subject, and most of us have struggled with trying to lose a few (or more) pounds at some point in our lives. Diets, exercise, supplements, seaweed wraps, hypnotherapy — you name it, and someone you know has probably tried it.
The problem is that results, if any, are often transient and hard to maintain.
Well, it turns out that we may be looking for solutions to our weight problems in all the wrong places. In our quest to eat less and exercise more, we're overlooking what may be the key to consistent and maintainable weight loss: our gut microbes.
You see, our gut houses trillions of bacteria that make up our microbiome, an ecosystem of good and bad bacteria that call our body their home. It may sound bizarre (and pretty disgusting) to know that we have so many "bugs" living in our body, but it's true — bacteria outnumber our human cells by roughly 10 to 1.
The good news is that we have a symbiotic relationship with our bacteria. We provide a home and food for the microbes, and they augment our health with an ever-increasing number of life-supporting functions.
From regulating our immune and nervous systems to assisting with digestion, producing vitamins and enzymes, protecting us from harmful pathogens, and even boosting our memory, it's no surprise that the friendly flora in our gut — the probiotics — play a starring role in our metabolisms as well.
The research is clear: Probiotics have a huge impact on our body weight and body mass index (BMI). In a recent meta-analysis, researchers analyzed nearly 2,000 adults from 25 trials and found that probiotic consumption reduced both weight and BMI, with improved results for subjects taking multi-strain probiotics and for those who took the beneficial bacteria for eight weeks or more.
In another study, women who took a daily dose of probiotics for 24 weeks showed significant reductions in body weight and fat mass compared to the placebo group.
So, how do probiotics help us manage our weight? Scientists are still hashing out the connection between bacteria and weight, but we do know that overweight people tend to have different gut microbial compositions than their lean counterparts. Specifically, people who struggle with weight issues seem to have more of a type of bacteria called Firmicutes, while lean individuals have more Bacteroidetes.
Why does this matter? Well, bacteria in the Firmicutes and Bacteroidetes families make up around 90 percent of all bacteria in our gut, so changes in their ratios can have a big effect on our health. And Firmicutes — due to their massive production of short-chain fatty acids — add to the number of calories we absorb each day, which may be one reason they are associated with being overweight and obese.
But, there's much more to the story. Just by positively affecting and supporting our many daily bodily functions, probiotics keep us healthy, happy, and (if in balance) at an optimal weight.
Here are the top 4 ways your beneficial bacteria work to keep you feeling and looking your best:
1. They improve nutrient absorption.
One of the primary roles of our gut bacteria is to help us digest everything we eat by breaking food down into molecules that we can absorb into our bloodstream for nourishment. Our gut microbes also produce vitamins, enzymes, and short-chain fatty acids, all of which contribute to our digestion process and metabolism.
So, how do probiotics help us shed excess weight? At the most basic level, beneficial bacteria help us absorb the nutrients from all the food we eat. This is important because, no matter how healthy our diet is, if we can't absorb nutrients from our food, we will always feel unsatisfied and hungry as our body craves adequate nutrition. In fact, studies show that unbalanced, unhealthy microbiomes lead to malnutrition due to a lack of nutrient absorption — regardless of nutritious food intake.
2. They regulate hormones.
Our good-guy microbes also help determine how full we feel by regulating hormones that send signals to our brain to stop eating. For example, probiotics affect leptin, a hormone made by fat cells that controls feelings of satiety or fullness.
Because the body's fat cells produce leptin, the more fat we have in our bodies, the more leptin our body makes to signal to the brain that we are full. This is the body's way of trying to stabilize weight. Unfortunately, a cycle of increased fat accumulation (i.e., from not listening to the body's fullness signals) leads to overproduction of leptin. Eventually, our system becomes clogged with too much of this master hormone, and the signaling process breaks down, leading to leptin resistance.
You see, even though we have plenty of the hormone in our body, our brain isn't getting the signal that we are full. It thinks we are starving and keeps telling us to eat. It turns out that probiotics can improve leptin sensitivity, so our brain gets the signal that it's time to stop eating.
3. They reduce inflammation.
Inflammation is a well-known precursor to metabolic syndrome, a group of risk factors — including high blood pressure, high blood sugar, abdominal fat, and unhealthy cholesterol levels — that can trigger obesity and type 2 diabetes.
Probiotics work by lining and protecting our gut barrier, keeping undesirable substances from entering our bloodstream. However, when our microbiome is out of balance and our gut barrier becomes too permeable (aka "leaky gut"), pro-inflammatory molecules and toxins can slip through, triggering allergic and immune responses that lead to systemic inflammation and the dreaded cycle of weight gain.
Beneficial bacteria both strengthen the gut barrier and regulate the immune system, 80 percent of which is in the gut.
4. They balance blood sugar.
In the same vein (no pun intended!), our blood sugar levels can have a dramatic effect on our weight. As with everything in life, balance is key, and our blood sugar is no exception.
If the level of glucose in our bloodstream is too high, our body stores the extra glucose as fat and the insulin — secreted by the pancreas in reaction to high blood sugar — signals the body to stop burning fat altogether. If our blood sugar is too low, we crave high-sugar foods to give us a quick energy boost, and the influx of glucose into our bloodstream triggers the vicious cycle of fat storage and weight gain.
Fortunately, research shows that probiotics work to support healthy blood sugar levels by improving insulin sensitivity and increasing insulin secretion. In one recent review, probiotic consumption was associated with lowered fasting glucose levels for subjects with type 2 diabetes.
Here's how to make you gut bacteria work for you (and your weight loss goals):
Research clearly shows that fortifying your gut with tons of good bacteria can help you lose weight and keep it off. So, what do you need to do to reap the benefits of bacteria?
Power up with probiotics.
When it comes to ensuring that you have plenty of beneficial microbes to support your healthy weight efforts, there's no substitute for a high-quality, effective probiotic supplement. Look for a broad-spectrum formula (with various strains from the Lactobacillus, Bifidobacterium, and Streptococcus families) that is designed to survive your stomach acids, ensuring the viable organisms are delivered into your gut alive. This is important because without protection, as much as 96 percent of the bacteria in many common probiotic supplements will be killed before they ever reach their destination and have a chance to support your health.
Avoid unnecessary antibiotics.
Just as it sounds, the function of antibiotics is to kill bacteria, both good and bad. So anytime you take antibiotics as medication or eat them in your food, they are killing the good bugs that you've worked so hard to nurture. Think about it like this: Conventional farmers use antibiotics to fatten up their livestock, so what are they doing to your body? Now, that's definitely food for thought!
Live a probiotic-rich life.
Unfortunately, so many things in today's culture deplete the good bacteria in our gut. From antibacterial cleansers and overzealous hygiene habits (dirty is sometimes good) to certain medications, pesticides, and processed-food diets, our probiotics have to fight hard to stay alive in the face of so many threats. Eating a whole foods diet, finding ways to de-stress, exercising regularly, spending more time outdoors, and steering clear of chemicals and toxins will help you live a natural life in harmony with your microbes.
Feed your friendly flora.
As you focus on establishing your population of good bacteria, make sure you are a good host and that you give them what they need to thrive. Probiotics' favorite food source is prebiotic fiber, so a high-fiber diet is your best bet for keeping them alive. Indigestible for us, prebiotic fibers give the good microbes what they need to keep you healthy (think of it as fertilizer to a garden). Try bananas, onions, garlic, Jerusalem artichoke, and apples for a prebiotic punch. Just remember, when it comes to prebiotic foods, the more unrefined, the better.
Although we are just beginning to understand how crucial probiotics are to our health and how exactly they support our weight and metabolism, one thing is for sure: Accomplishing your goals is about so much more than just counting and burning calories. Making the choice to support your microbial health on a daily basis may very well be the missing component on your journey toward sustainable weight loss and optimal living.
Jamie Morea is a microbiome expert, gut health evangelist, and co-founder of the probiotic company, Hyperbiotics. She has been working in microbiology research and development for the past ten years and is devoted to making a difference by leveraging the latest scientific research to educate, inspire, and empower individuals on their journey toward greater health.