Your gut and your brain are in constant communication. This is not really surprising, as essentially everything in your body is connected, as I've noted before. But some connections are stronger than others.
Your gut contains zillions (really scientific term) of bacteria, which are not only helping you to digest what you eat but are also releasing what to them are waste products but may be active compounds that will get into your circulation and affect your physiology.
In other words, you should be kind to your gut bacteria as much as you can because if you are, they will help you. This means if you have killer bacteria in your gut, it makes sense to take an antibiotic that will kill these bacteria. Then it makes sense to repopulate your gut with good bacteria, for example, by eating foods like yogurt that contain a lot of microorganisms.
But it doesn't make sense to take antibiotics when you don't need them, for example for a viral infection that isn't affected by antibiotics.
This recent research shows that your gut bacteria can affect your appetite, which is very relevant to type 2 diabetes. If you have a ravenous appetite it's difficult to limit what you eat, and limiting what you eat along with getting exercise is the best way to control type 2 diabetes.
Not everyone can do this if the disease has progressed with time either before or after you were diagnosed, and then drugs, including insulin, may be necessary. But it doesn't hurt to try.
I used to have a huge appetite. Someone once remarked that they'd never seen anyone so small eat so much. But with time, I don't know if mostly because of increased age or habit, my appetite has decreased so I now find the portions you get in restaurants to be too large. As I can't stand to waste food (some ancestors were Scottish) I now, when I go out, carry my own doggy bag, a plastic thing with dividers that fits inside a purselike bag. I can put the extra food in that and avoid juggling those big Styrofoam containers restaurants usually give you with leftovers. And walking down the street, I don't let everyone know that I'm carrying food.
Dogs aren't fooled, however.