New book claims overall health starts with the gut

— -- The author of a new health guide that calls for focusing on the well-being of your gut spoke out in an interview with "Good Morning America," claiming that the gut is the key to unlocking a myriad of other health benefits.

"So many times people say, 'Whatever diet I go on, I can't lose weight. I don't know why. I can't lose weight,'" Jeannette Hyde, a nutritionist and author of "The Gut Makeover: 4 Weeks to Nourish Your Gut, Revolutionize Your Health, and Lose Weight," told ABC News. "I think that maybe that you need to unlock the key of this balance, of your bacteria ... so you can control your weight better."

In the past, Hyde said doctors believed that gut bacteria "was something completely benign" and not "of any medical interest whatsoever ... it was totally ignored."

"Then in the last few years there's been a tsunami of research into this gut bacteria," Hyde said. "It's called the microbiome, and suddenly it was like 'Oh God, there's miles more of this stuff than we ever thought."

"We've got trillions of this bacteria living in the gut," Hyde added, saying that the average person has three or four pounds of bacteria in them. "And the researchers have discovered that it's really powerful stuff.

She continued: "It is having an influence over many, many areas of our, health including our weight. It also has a big impact on our immune system."

Hyde also explained that a healthy gut leads to better mental well-being as well.

"The other big thing that it ... helps a lot is our mental health," Hyde said. "Whoever thought that our mood was partly being influenced by the bacteria that's in our gut?

"The science is backing this up as well, that when you eat to feed the bacteria in your gut, and get that thriving, that has an impact on your weight, with no calorie counting," Hyde added.

Hyde's 28-day plan, outlined in her new book, works to improve your gut health by eliminating sugar, wheat, alcohol, caffeine and dairy during the first two weeks. She also advises to avoid antibiotics and dramatically increase your intake of gut-friendly foods.

"This plan is all about abundance. Not deprivation," Hyde said. "The main thing is you want to get in as much fiber and as much color into your diet as you possibly can."

She adds that she encourages people to "get up to 30" fruits or vegetables in their bodies per week.

Hyde recommends eating food from two major groups, "prebiotics," or fruits and vegetables, and "probiotics," or fermented food such as kefir milk, Roquefort cheese, tempeh and live miso.

Emily Ritter, 28, decided to try the health plan after indulging in a junk food-filled holiday season, calling the regimen a "makeover for your stomach."

"It was really hard, but in the end, I felt really good about all of the things I learned, all of the foods I tried, and just my body and my stomach felt so much better," Ritter told ABC News, adding that she lost eight pounds in a few months of the plan.

Other tips Hyde gives for improving the health of your gut include not eating for 12 hours in a day, or trying to eat three meals with no snacks in between. For a more affordable option, she recommends trying frozen fruits and vegetables.

"The Gut Makeover: 4 Weeks to Nourish Your Gut, Revolutionize Your Health, and Lose Weight" hits bookstores nationwide today.