The Swift Diet: How to Eat for a Healthier, Leaner Gut

Nobody sits around thinking about his microbiome — that microscopic bacteria in the gut. But purposely eating to better feed these bacteria can go a long way to keeping you lean, along with reducing muscle and joint pain, clearing skin, boosting energy, and aiding in digestion. Doing so is simpler with the advice from Men’s Journal contributor Joseph Hooper and nutritionist Kathie Madonna Swift in their new book The Swift Diet, out today. We cherry-picked five simple tips to help you make it happen.

1. Load up on Fiber
A diet rich in veggies, fruits, and legumes feeds the friendly bacteria living in your colon. Skip or go light on these food groups, and the gut environment becomes toxic: bad bugs, fungi and parasites move in and can escape into the blood stream, triggering inflammation throughout your body. One example of this "leaky gut syndrome" is insulin resistance, where the body stores more calories as fat instead of burning that fat for energy. A study published in Nature found that lean people actually have a greater number and greater diversity of gut bacteria than overweight people. When some of the overweight people went on a higher-fiber, lower-calorie diet, their microbiota started to resemble that of the thin people. In other words, what they ate changed their gut bacteria to support losing weight.

2. Cut Back on Added Sugars
When we’re getting most of our calories from refined carbs like grains or flour-based foods, we’re almost always not eating enough plant fiber, starving the friendly bacteria in the colon. This creates an inflammatory double-whammy: On top of the possibility of leaky gut syndrome, the body quickly absorbs the calories in the refined carbs into the small intestine, which drives up blood sugar levels. In turn, that drives up the body’s production of insulin needed to escort the sugars into the muscle cells and the liver. The result? You burn fewer calories, and store more as fat. Even worse, the extra body fat secretes its own inflammatory hormones. So besides a spare tire, you could develop insulin resistance, and worst-case scenario, Type 2 diabetes.

The main dietary offender is sugar added to processed foods. The worst of the worst is sugar in sodas, teas or even fruit juices. The body doesn’t compensate for these liquid calories as effectively as it does the calories in solid food so you’re more likely to overeat at your next meal. The solution is straightforward: Choose whole foods over processed foods, which also contain mass-produced vegetable oils that can drive up inflammation.

3. Test for Food Sensitivities
Common ingredients such as gluten in grains or lactose in dairy can contribute to weight, energy, skin or even mood woes if you have a sensitivity to them — which is a surprisingly common problem. Often, a depleted microbiota is part of the story. Without numerous and diverse gut bacteria, your microbiome won’t be able to help your immune system accurately distinguish friend from foe (we see this happen when someone has an inflammatory overreaction to gluten, an otherwise harmless protein compound found in most grains).

An unbalanced gut can also over-feed on lactose, causing a host of unpleasant digestive symptoms, such as queasiness and excess gas. So experiment. Take grains and dairy out of your diet for two weeks or three weeks, then introduce them back in one at a time to see if they’re causing problems. You may feel lighter and more energetic without them.

4. Add more Herbs and Spices to Your Diet
These are nature’s most potent anti-inflammatories. Herbs and spices such as turmeric, rosemary, cloves, and ginger contain antioxidants that drive down disease-causing processes. A study from the University of Florida found that a well-spiced dish could reduce the amount of inflammatory cells that the body produced after it was exposed to typical inflammation-causing food, such as a plate of fried chicken.

5. Take Note of Stress Levels
If you’re constantly anxious, research shows your body’s overproduction of stress hormone can alter your microbiome to favor the unfriendly bacteria over the friendly. Anything you can do to bring stress under control will help, especially exercise. One study of professional rugby players in Ireland found that the athletes had a more diverse collection of gut bacteria, helping them stay healthier than their same-sized, non-jock counterparts.