I am very firm against the "one size fits all" phrase. We are all different, with different sizes, beliefs and likes/dislikes. This is just as true for nutrition as everything else. We are all different, with different digestion, likes, tolerances and systems. I, for one, have found I just can't eat meat. My body doesn't like it, doesn't digest it properly, and I personally don't like it - so I have become a vegetarian and am very happy with this lifestyle. On the total flip side of that coin, I have a good friend who's husband is literally allergic to vegetables. After only a few bites into a salad his throat will start to itch and swell up on him. I have friends/relatives that are diabetic, have celiacs disease, or are lactose intolerant. This list goes on and on, so diet is really different for each one of us. However, there are 5 rules of nutrition that I think we should all follow, regardless of our individual needs or tastes.
1. Eat Whole, Natural Foods
I don't care what kind of diet you are on, make sure the ingredients of your meal are as close to the natural state of that food as possible. Stay away from processed foods as often as possible and eat as many one ingredient dishes as you can. If you are eating a packaged food, read the label. If it has more than half a dozen ingredients in it, you don't know what something is, and worse yet can't even pronounce an item on the list, put it back. Our bodies were designed to eat food in it's natural state and doesn't know what to do with all of the lab experiments that are on our grocery store shelves. Stick to the perimeter of the store, by fresh, and by whole.
2. Keep The Sweets Down
Even in their natural states, the body can only handle so much sugar at one time. Try to get your pallet used to eating things a little less sweet. Honey, syrup, agave and the like are not bad for you in their natural - unprocessed state, but in small quantities. I use honey and pure maple syrup in almost all of my recipes that need a bit of sugar, but I use them very sparingly and most of my stuff doesn't turn out super sweet.
3. Keep The Fat Low
Fat is good for us. Our body needs fat to keep our insides lubed and our brain uses fat to function. We cannot survive without fat. However, we get plenty of fat naturally in the foods we eat, when consumed in their natural states. Nature is not dumb. She knows what we need and does a very good job of providing it for us. Therefore, ADDED fat is not needed. Keep the fat in recipes low, saute in broth or water instead of oil, and (I know, I know) don't drown things in butter, mayonnaise or sour cream. Again, get used to eating and tasting foods how they were meant to be eaten without smothering them is fats and sugars.
4. Water
Our bodies are made up of mostly water, it therefore makes sense that we need to keep that water replenished at all times. If you are active - as you should be - it is even more important to keep the water coming. It helps your body function properly, keeps the blood flowing the get all of those wonderful nutrients you are eating in the right place, and keeps your system flushed of any build-up. If you are eating properly, and drinking plenty of water there should never be a reason to do "a cleanse". Your body was designed to take care of all that on it's own, if given the proper tools to do so.
5. VARIETY!
Variety is the key of life. If you are eating a wide variety of foods, it keeps you from getting bored and it ensures that you are getting all of the nutrients you need. There is no such thing as a super food with everything you need packing into one amazing package. In order to get everything you need, it has to come from many different places, so keep variety in your diet will make sure that happens. Besides, how boring would it be to eat the same thing every single day?! I make it a practice to try at least one new recipe a week - or at least one or two a month if I am on a very busy schedule. Yes, we have has some very interesting meals, but on a whole they have all been at least tolerable, and how else are you gonna find those gems if you never try new things?