Health Watch: How your body reacts to raw vs. cooked food

Humans have been heating their food for nearly 2 million years. Before that, raw foods were the main source of food.

But they have been linked to diseases such as E. Coli, salmonella, staph, mercury poisoning and listeria. So, does cooking your dinner change the way your gut processes the meal?

Cold or slightly warm, raw foods are everywhere, from fruits to nuts and even sushi. There's been a 92 percent increase in raw food orders in the past year.

Raw food studies have linked raw food to weight loss, where men are nearly 15 percent under normal weight range and women are 25 percent. But that's not the story.

A new study by the University of California San Francisco and Harvard University shows raw and cooked foods might each have a different impact on your gut microbiome. That's the collection of microbes that live in your intestines and help you digest food.

Seema Bhatnagar, PhD, Associate Professor of Anesthesiology, University of Pennsylvania says, "The gut microbiome is a major source of immune-inflammatory molecules, some of which can access the brain."

Researchers from the schools found mice that ate sweet potatoes developed significantly different microbiomes when the foods were consumed raw.

In fact, the animals on the raw potato diet had poorer bacterial diversity in their gut, fewer bacteria, and lost more weight.

Scientists then repeated the study in humans and again found clear differences in gut bacteria when the participants were exposed to raw foods and cooked foods.

Other studies have shown cooking food can alter its nutritional components and may provide more energy. Researchers say they want to continue studying the effects of raw versus cooked foods to learn more about how they affect your body.

Interestingly, the scientists found that the mice's gut microbiome didn't change much when they were fed raw or cooked meat. Only the starchy potatoes had a dramatic effect.

They say this is likely because potatoes have a high quality of low digestibility, which has properties that are transformed by heat.

Contributors to this news report include: Julie Marks, Field Producer; and Roque Correa, Editor.