There have been several recent studies showing that people who have inflamatory diseases, those with conditions like PCOS, those with diabetes and those who are obese have different gut bacteria compared to healthy people.
The main issue is that their gut bateria is less diverse than that of healthy people. According to Scientific American,
In studies of twins who were both lean or both obese, researchers found that the gut community in lean people was like a rain forest brimming with many species but that the community in obese people was less diverse—more like a nutrient-overloaded pond where relatively few species dominate. Lean individuals, for example, tended to have a wider variety of Bacteroidetes, a large tribe of microbes that specialize in breaking down bulky plant starches and fibers into shorter molecules that the body can use as a source of energy.
Gut bacteria is important, it manufactures a lot of the B vitamins you need for health, as well as produces hormones like serotonin which regulate wellbeing.
It appears that in people who are unhealthy, the bad bacteria has killed off the good, reducing the diversity in the gut.
So how to restore the health of your gut?
First go on a fast
Bacteria need food to live, and if you want to shrink the amount of bad bacteria in your gut, fasting is the easiest way. Make sure you drink a lot of water while fasting - you'll need to poop out the dead bacteria, and drinking a lot of water will help the passage out.
Don't do a total fast for more than two days
Now repopulate your gut
Eating fermented foods are the best way to do this.
Try sauerkraut, dill pickles, miso soup, tempeh, kimchi, yogurt and sourdough bread.
You can make your own fermented vegetables by packing them tightly in a mason jar with brine. The brine will react with the food to produce lactic acid (which preserves the food and gives it it's sour taste) and probiotics. Within a week, you have some fermented vegetables.
In addition, add some dark green vegetables to your diet. Try and eat something different each day - the more diverse your diet, the more diverse your gut bacteria.
Add meat to your diet slowly and in small amounts
If you are still suffering from bloating and yeast infections try Manuka Honey
Manuka is also known as Teatree, and the honey is produced by bees exclusively gathering nectar from the manuka flowers. Manuka is a strong anti-bacterial plant, and the honey has anti-bacterial properties as well.
Eat the manuka honey on a piece of white bread, four times a day. At some point you will pass out a lot of stuff (that's the dead bacteria that has been plaguing you), and then feel wonderful once it has gone.