Scientists find link between gut microbiota, diet, and weight gain.

Moral of the story: What you eat matters. A lot. The link between diet and weight is rather complicated and taking out fats and sugars can help to change the fauna of your stomach to help you lose weight. Chewing gum and breastfeeding help shed pounds too.

Source: AMA Morning Rounds 11/12/09

Scientists find link between gut microbiota, diet, and weight gain.

The Los Angeles Times (11/12, Maugh) reported, "A high-fat, high-sugar diet does more than pump calories into your body. It also alters the composition of bacteria in your intestines, making it easier to gain weight and harder to lose it," according to a new paper in Science Translational Medicine. What's more, the "changeover can happen in as little as 24 hours."

Technically known "as the gut microbiota," intestinal "microbes perform a vast range of vital functions, including helping to regulate the calories the body obtains from food and stores as fat," according to Time (11/12, Park). Through earlier experiments, however, Washington University researchers found that the "gut microbiota of obese mice...have significantly more of one main type of bacteria called Firmicutes, and fewer of another kind called Bacteroidetes (both types populate human guts as well); in normal mice, the distribution is the opposite." With that in mind, the team devised a new study in which human microbiota was used "to colonize mice guts." The rodents were then fed "equivalents of typical human diets to see how their microbes -- and their weight -- might change."

Lead investigator Dr. Jeffrey I. Gordon told HealthDay (11/11, Gordon) that when his team "switched these humanized animals [from a low-fat] to a junk-food diet, high in fat with lots of simple sugars, the structure of the microbial community changed dramatically and very rapidly." What's more, the mice "became obese on Western diets." Investigators also discovered that "the microbiota passes from generation to generation."

Study points to chewing gum as weight loss aid. The Washington Post (11/11, Huget) reports that for anybody trying to lose weight, "taking up gum-chewing might not be a bad idea," as "there's actually a bit of scientific evidence showing that chewing gum helps fight fat in a number of ways." The research, sponsored by the Wrigley Science Institute, has suggested "that chewing gum may help reduce cravings, particularly for sweet snacks, and spur people to cut their daily intake by about 50 calories." The findings were presented at the annual scientific meeting of the Obesity Society last month, and "showed that gum-chewing people consumed 67 fewer calories at lunch and didn't compensate by eating more later in the day."

Breastfeeding's effect on postpartum weight discussed. The New York Times (11/12, E3, Louis) reports, "That breastfeeding gives mothers an edge shedding baby weight has long been suspected." A Danish study published last year showed that "the more a mother breast-feeds, the less weight she retains six months after birth." But, other research has shown that "breast-feeders don't necessarily shed fat quicker than women who feed their newborns formula." Meanwhile, "a small double-blind randomized study conducted at Cincinnati Children's Hospital Medical Center found that non-lactating women lost more body fat than lactating women at six months, and at a faster rate." Still, "others suggest that women who view breast-feeding as a dieting tool may have 'deeper body issues.'" One expert said "she was troubled by our cultural preoccupation with postpartum weight."