Your Body’s Hidden Organ

Digestive System

Rodale News

This Q&A with Gerard E. Mullin, MD, a gastroenterologist, nutrition expert, and author of The Gut-Balance Revolution: Boost Your Metabolism, Restore Your Inner Ecology, and Lose the Weight for Good! dives into the growing research about the millions of microbes that live in our stomachs.

Rodale News: Briefly, how does The Gut Balance Revolution work?

Gerard Mullin, MD: The gut bugs control our appetite. It’s about making your bacteria more efficient by eating foods that are good for them. Everyone is different, but typically within two weeks people [on The Gut Balance Revolution diet] start noticing weight loss. Even if they are immobile, they will burn fat. They spark weight loss by sparking better metabolism.

In the first month, we eliminate starches and consume low carbs to induce fat burning. In the second phase, we introduce fibrous carbs to promote a richer mix of good bacteria; we diversify the mix of fruits and veggies. You exercise so you don’t lose muscle. You start to feel more energetic, as the weight loss continues.

Phase 3 is a maintenance, integrating a long-term, flexible, a sustainable eating plan that will help you keep the weight off. I want you to have the tools to achieve and maintain optimal weight, health, and gut microbiome balance for life.

RN: What is meant by gut flora?

GM: It’s the balance of bacteria and different organisms that determine many bodily functions, like digestion, elimination, and detoxification. Research in this area has exploded the last four or five years since the Human Microbiome Project (HMP). [The “human microbiome” refers to the different kinds of microbes that live on and inside us. In 2008, the National Institutes of Health launched the HMP, a five-year-initiative to learn about the microorganisms found in both healthy and diseased humans. Researchers studied the microbes’ DNA, other chemicals that the microbes produce, human DNA, and how microbes interact with each other.]

We’re beginning to understand that your gut microbiome has a far broader impact on your health and weight than scientists originally knew. The influence appears to be so strong that some researchers refer to the gut microbiome as a “hidden organ” whose health is a strong indicator of your long-term weight and well being.

RN: In your book, you point to the Standard American Diet (SAD)—which is high in inflammatory fats, high in processed carbohydrates, and low in fiber—as negatively impacting gut flora.

GM: The more diverse your gut microbes are, the healthier you are. The SAD diet shifts the relative balance of bugs in your gut toward fat-forming bugs. After eating a high-fat meal, this shift can occur dramatically, in as few as 24 hours.

Reversing this trend means cutting back on inflammatory fats, dramatically reducing your sugar intake, and increasing your levels of fiber. It’s really about the way food is influencing the types and balance of bacteria in the gut.

RN: You write that losing weight successfully is much more complicated than calories in and calories out. Can you please explain?

GM: [The quality and diversity of] gut bacteria influence the efficiency of one’s metabolism. There are plenty of people cutting calories and still gaining weight. That’s because their metabolisms are so imbalanced they are not really burning all the calories they can.

Several studies have shown that your body weight set point remains fairly constant. In other words, your body gets acclimated to a certain weight. The body weight set point theory suggests that the human body evolved to adapt to periods of low food intake, protecting itself from starvation by holding on to fat. As you lose weight, your body tricks you into eating more. Your appetite increases. Your body is doing everything to fight you (from losing weight). In other words, yo-yo dieting can raise your set point so that your metabolism will slow to maintain higher body weight and fat. And that’s the real problem with yo-yo dieting— every time your weight rebounds, your set point gets pushed higher, so your body acclimates to the new body weight set point as “the new normal.”

RN: Why else do many of us find dieting so difficult?

GM: Margaret Mead said, “It is easier to change a man’s religion than to change his diet.” Sticking to a diet is hard. You have to be motivated; to believe you can do it. Your family has to be willing to adapt to your new food requirements.

RN: Do you think the research about the gut microbiome (microbial communities) will prove a game changer for dieting?

GM: My own experiences have shown me that people who follow the right diet and have a good approach to gut bacteria, lose that stubborn fat. This is a program for life. It’s not about dropping 20 pounds in 20 days. It changes you inside out. People feel years younger.

We’re really redefining people’s health. It’s a process to change your microbiome. You don’t just flood the body with yogurt. You have to shift the terrain. I liken it to gardening—you have to prepare the soil. Fertilize. You don’t just dump in the fertilizer and say this will all just magically fall into place.