Coveting celebrities' body parts is nothing new. We pine for Zooey Deschanel's big blue eyes, and Sofia Vergara's dangerous curves, but there's one body part that perhaps we need to be more envious of: the gut. Or, more specifically, the contents of it.

According to new research in mice, the creepy-crawly bacteria that live and breed in our bellies may make all the difference between whether we flaunt an apple or hourglass figure. Dr. Jeffrey Gordon from Washington University in St. Louis , who conducted the study, believes that the hundreds of different bacteria that live in our guts may influence how well we burn - or store - fat, and can either spur obesity or protect against it.

To test his theory, Dr. Gordon took several groups of human twins, where one was obese and the other thin and transplanted their gut bacteria into mice who'd been raised in sterile cages without ever being exposed to bacteria-- like bubble boy -- then waited for the results. The mice injected with the fat flora gained weight while those who got the lean stuff stayed thin -- even when they were all fed the same diet.

Dr. Gordon then put the mice in the same cage to see what would happen if they swapped gut bacteria. "Oh, how do they do that?" you ask. Well, mice like to eat each others feces, which means plenty of bacteria-sharing for all!. Yeah, we were pretty grossed out, too. The mice originally injected with the "fat" microbes adopted the bacteria of the thin mice and began losing weight. Thankfully, eating the obese mouse's germs had no effect on the thin mice. The results suggested that the bacteria in our bodies not only affect our weight, but that we can lose weight just by changing our gut bacteria.

So how do you go about getting skinny people germs -- save the unthinkable?

Promising new research shows that getting thin people bacteria might be as simple as changing what you eat: Think low-fat and high-fiber foods. So, no, cheeseburgers and pizza won't cut it.

Here, a closer look at the best foods to get your skinny bacteria growing.

Switch out your faux sweeteners or daily sugar fix for honey, which is loaded with prebiotics. If you're new to the whole gut health thing, you may not know the difference between a probiotic and a prebiotic. Prebiotics are non-digestible carbohydrates in food that our friendly gut inhabitants eat to help them multiply. Probiotics are live "good" bacteria -- like those in our gut -- found in foods like yogurt. Eating probiotics is like sending in reinforcements to fight off the bad bacteria that also reside in your gut.

Apples contain pectin, a type of fiber shown to increase certain types of bacteria (and -- bonus -- may improve your digestive plumbing), according to microbiologist Andrea Wilcks. Her research on the benefits of apples found that eating them regularly (think: an apple a day), creates an ideal environment in your gut for maintaining a good balance of microorganisms.

The fibrous flesh of Jerusalem artichokes is also a prebiotic filled food. The indigestible fiber in Jerusalem artichokes feeds friendly bacteria, and starves the bad.

Before you run to the grocery store to grab as many as possible, make sure you know what Jerusalem artichokes look like. They aren't really artichokes at all. They're actually the root vegetable of a type of sunflower. While traditional artichokes are a good source of fiber, Jerusalem artichokes have two to three times the amount as the regular variety. If you're trying to kick your gut germs into gear opt for Jerusalems.

Chicory root contains inulin fiber, a prebiotic often used as a food additive in processed foods and probiotic supplements. But inulin is most effective in its natural state. It can be used as a natural sweetener and caffeine-free coffee substitute. (Look for chicory-laced coffees like French Market Coffee or Teeccino, a coffee substitute sold in health food stores.) If you're not a coffee drinker, you can also eat the leaves raw like celery.