“I read somewhere that a high-fat diet can damage your gut bacteria and promote weight gain,” writes this week’s house call. “Should I be concerned if I’m eating a high-fat diet?”

It is true that what you eat can affect your gut bacteria, for better and for worse, and changes in your gut bacteria or microbiome cause weight gain.  Indeed, some studies demonstrate that high-fat diets can adversely affect your gut flora and promote inflammation and weight gain. However, it’s important to note that the type of fat you eat matters!  Most of these studies are focused on diets that incorporate high levels of inflammatory, refined omega 6 vegetable oils like soybean oil. 

Refined omega-6 rich vegetable oils fall into the “bad fats” category and should be avoided. While most of us have been convinced, by the food industry and our government, that vegetable oils are safe and a heart-healthy alternative to saturated fats, we now know differently.

Polyunsaturated fats from soybean, canola, and other seed oils are inflammatory. Avoid them if you want to be healthier. Even if you consume some omega 3 fats while consuming these inflammatory oils, you won’t reap the healthy fat benefits.

For most of human history, we consumed a much higher ratio of omega 3 fats to omega 6 fats. Wild foods like grass-fed beef and wild-caught fish provide a great source of omega 3s, but these foods are not a big part of our modern diet. Unfortunately, the factory-farmed animals that do make up much of our modern diet have almost zero omega 3 fats.

The vast quantities of omega 6 fats in our diet contribute to heart disease, diabesity, and cancer. Studies also link high omega 6 fat consumption to depression, suicide, and other major health problems due to increased inflammation.

To reverse these and other problems and create optimal health, replace these damaging omega 6 fats with healthy ones – like coconut oil, avocados, grass-fed butter, fish rich in omega 3s, and extra-virgin olive oil.

Interestingly, when we look at studies that use the healthy, anti-inflammatory omega 3 fats, we see just the opposite effect. These healthy fats promote healthier gut bugs, lower inflammation levels, and increased weight loss.

I said it before and I’ll say it again:  the types of fat we eat matters. The wrong fats increase inflammation, promote the growth of bad bugs, and create resistance to weight loss. The right fats decrease inflammation and help with weight loss.

Why Is Gut Health So Important?

Optimal gut health has become a prominent focus in 21^st century health. Having too many bad critters hanging out in the gut has been linked to numerous problems – including autism, obesity, diabetes, allergies, autoimmunity, depression, cancer, heart disease, fibromyalgia, eczema, and asthma. The links between chronic illness and an imbalanced microbiome (or gut bacteria) keep growing every day.

Many scientists have begun to refer to the gut as our second brain, an idea that is reflected in amazing books like The Good Gut, Brainmaker, The Microbiome Solution, and The Gut Balance Revolution.

Having a healthy gut should mean more to you than being annoyed by a little bloating or heartburn. It becomes central to your entire health and connected to everything that happens in your body. That’s why I almost always start treating my patients’ chronic health problems by fixing their guts first.

You can begin to understand the importance of gut health when you consider there are 500 species and three pounds of bacteria in your gut. There are trillions of bacteria in your gut, and they collectively contain at least 100 times as many genes as you do. The bacterial DNA in your gut outnumbers your own DNA by 100 times. You have about 20,000 genes, but there are 2,000,000 (or more) bacterial genes!

Altogether, your gut is a huge chemical factory that helps to digest food, produce vitamins, regulate hormones, excrete toxins, produce healing compounds and keep your gut healthy.

Intestinal health could be defined as the optimal digestion, absorption, and assimilation of food. But that is a big job that depends on many other factors. For example, the bugs in your gut are like a rain forest – a diverse and interdependent ecosystem. They must be in balance for you to be healthy.

Too many of the wrong ones (like parasites, yeasts or bad bacteria) or not enough of the good ones (like Lactobacillus or Bifidobacteria), can lead to serious damage to your health.

Optimal gut balance begins with your diet, which directly affects that balance. You want to eat a diet with lots of fiber, healthy protein, and healthy fats.

Good fats, including omega 3 fats and monounsaturated fats – such as extra-virgin olive oil, avocados or almonds – improve healthy gut flora, while inflammatory fats, like omega 6 vegetable oils, promote growth of bad bugs that cause weight gain and disease.

Even obesity has been linked to changes in our gut ecosystem, resulting from an intake of inflammatory omega 6s and not enough anti-inflammatory omega 3s. Bad bugs produce toxins called lipopolysacchardies (LPS)  that trigger inflammation, insulin resistance or pre-diabetes and therefore, promote weight gain.

Lack of sleep and chronic stress also contribute to gut imbalance, In fact, your gut flora listens to and becomes influenced by your thoughts and feelings.  So be sure to get 7 to 8 hours of quality sleep and remember to practice your favorite stress reduction activities daily. 

9 Ways to Optimize Gut Flora

The best way to grow a healthy inner garden and make your gut bugs happy begins with your diet. Here are 9 ways to build healthy gut flora starting with your next forkful:

1. Eat whole, unprocessed, unrefined foods. One of the best ways to maintain gut health involves cutting out the sugar and refined carbs and jacking up gut-supporting fiber.
2. Make 75 percent of your plate be vegetables and plant-based foods.Your gut bugs really love these high-fiber plant foods.
3. Eat good fats and get an oil change. The good fats we mentioned earlier (like omega 3 fats and monounsaturated fats, such as extra-virgin olive oil) will help with decreasing inflammation, giving healthy gut bugs a chance to flourish.
4. Supplement smartly. Beyond the numerous benefits (including reducing inflammation), studies find omega 3 fatty acids can support healthy gut flora.  You should definitely supplement with an essential fatty acids formula, if you’re not regularly eating wild-caught fatty fish.  You can find professional-quality formulas in my store. Take a good probiotic supplement. This helps reduce gut inflammation while cultivating health and the growth of good bacteria.
5. Add more coconut. Studies demonstrate anti-inflammatory and weight loss benefits from adding Medium Chain Triglyceride or MCT oils. One of my favorite fats, coconut oil and coconut butter, contains these fabulous fat-burning MCTs.
6. Remove inflammatory fats. Cut out bad, inflammatory omega 6 rich fats like vegetable oils. Replace these with healthier oils like extra-virgin olive oil and coconut oil.
7. Add fiber-rich foods. Nuts, seeds, and a special fiber calledglucomannan provide prebiotics and feed our healthy bacteria.
8. Add fermented foods. Sauerkraut, kimchi, tempeh, and miso contain good amounts of probiotics so your healthy gut bugs can be fruitful and multiply.

The above recommendations are not miracle cures.  They are the actions that lead to normalized gut function and flora through improved diet, increased fiber intake, daily probiotic supplementation, the use of nutrients that repair the gut lining, and the reduction of bad bugs in the gut with herbs or medication.

Yes, inflammatory fats will definitely damage your gut bacteria. But the right fats, including omega 3s and extra-virgin olive oil combined with a whole, real food diet can actually repair your gut and even increase good bacteria.

My new book, Eat Fat, Get Thin, challenges conventional wisdom about what constitutes healthy oils and documents the research that debunks our old ideas about fat.

Wishing you health and happiness,

Mark Hyman, M.D.