I'll second what FeatherLight said. Definitely don't eat lots of carbs. Proteins and fats are what you need most of. But do eat some carbs because some of them are beneficial and necessary. Try getting your carbs from raw fruit if you can--it's one of the best ways. (Even better, if you have a blender, make smoothies from raw fruit--combined with a base like plain yogurt or something. Depending on the fruit, you might want to add some extra sweetness; apples, pears, and grapes are all good for that, as well as natural sweeteners like monk fruit, stevia, and sugar alcohols like xylitol and erythritol.)
But while we're talking about carbs, I have to mention how harmful refined grains can be. If you can at all manage to stay away from wheat in all its many forms, you will be better off for it. Also try to steer clear of things like white rice, and opt for brown instead. Refined grains are a major cause of so many people having diabetes--they spike your blood sugar which isn't good for your pancreas and can reduce your body's ability to self-regulate. Look for things with a low Glycemic Index (GI).
For protein, stick with things like turkey, chicken (if you're not a B blood type), and lean beef (unless it's grass-fed, in which case don't be afraid of fattier cuts because it's actually good for you). Beans can be good for protein as well, but don't forget tree nuts--they're also rich in minerals, which are very important to have in your diet. Some good ones are walnuts, pecans, and brazil nuts.
Fats are a hard one because you really need them, but most fats you'd typically eat aren't that good for you. Typical cooking oils won't be of any help to your body (like canola, soybean, vegetable, etc.), and animal fats can hold toxins generated by the mass-market breeding process. DEFINITELY stay away from ANYTHING FRIED. Even if it says it contains no trans-fats, don't believe it. Frying always creates trans fats. Chances are, it has less than the FDA says it has to have in order to be specified on the label. But even if it did have none, the frying process creates plenty of other toxins that are even more harmful that trans fats.
One of the best fats is coconut oil, which is mostly medium-chain triglycerides (MCTs). Your body can use those in some pretty nifty ways (mainly for energy) compared to all other fats. If you want, you can even buy pills of MCTs. If I recall correctly, they even reduce your risk of heart disease.
In a nutshell, the best diet has lots of vegetables, a medium amount of fruit and meat, and minimal other carbs. Lastly, some pills almost everyone should take regularly: probiotics, enzymes, and vitamin D. Probiotics keep the bad bacteria in your gut from flourishing and thus making you sick; enzymes help you to thoroughly digest your food to get the most nutrition out of it and to avoid gut bacteria having to process it for you (which leads to things like gas and diarrhea); and vitamin D because most people these days are low on it, due to the modern mostly-indoor lifestyle. It wouldn't hurt to get your doctor to check your vit. D levels though before starting a regimen. It is possible to overdose--though extremely unlikely for most people. I personally have a disorder that seems to be caused by low D levels, and (when I have it) I try to take about 15,000 IUs per day. I buy NOW brand D softgels that are 5,000 IU per softgel. And when I take it consistently, my muscle spasms go away. FWIW.
Hope that helps.
