(this is part 1 of 2, part 2 is here)
Dieting is nothing new. We (like all animals) have a biological drive to eat all the food we can find as fast as possible, in case it runs out or gets stolen by a hyena. Early society had to create rules around food that made group cohesion more important than any selfish individual, or everyone would have ultimately starved. Few people would consider the South Beach Diet a modern version of sacrificing a goat to make it rain, but in many ways it's the same thing. The rules are different because the cultural priorities are different, but essentially it's society saying "you can't just eat whatever you want all the time." You can't control yourself, so social pressure will do it for you.
In modern society, we've mostly removed the religious imperatives for controlling your diet, and replaced them with personal imperatives like weight, or medical imperatives like high cholesterol or diabetes. So now people are in charge of making their own rules, and this is a problem because most people one, don't know how digestion works, two, think that being thin and being healthy are the same thing, and three, are overwhelmed with advertising every waking minute of the day. All of these things make people susceptible to fad diets.
Raw food is a fad diet. One of my pulse diagnosis teachers has told me that this is the third raw food wave he's seen in his 30-year medical career. Eating raw food is terrible for your body. One of the reasons humans have been so successful at the evolution / survival game is because we cook our food. Other large primates spend fully one third of their waking hours chewing, that's how much raw food you need to eat in order to sustain your body. The reason for this is that you can't absorb most of it. Essentially, cooking starts the process of digestion, and if you don't cook your food, your body has to work that much harder to get useful calories out of what you're eating. Some people are thinking "great! My body has to work harder, so it will burn more calories, and I'll lose weight!" Except in reality, your body just won't get those nutrients at all. You'll probably lose weight, but you'll be malnourished, and it's not sustainable. Richard Wrangham has a book called Catching Fire: How Cooking Made Us Human that talks more about this topic, if you're interested from an evolutionary perspective. The point is, cook your food.
Gluten free is a fad diet. Yes, of course there are real gluten allergies, and they are more common than they used to be. (Allergies in general are more common, and there are theories about why but nothing has been proven. That's a problem for another post.) The demand for gluten-free products exponentially exceeds the actual incidence of Celiac disease. I know a lot of people who say they feel better than ever after cutting out gluten, and I believe them. I just don't believe that gluten is the problem. Most of the wheat products we're eating today are so processed that your body barely recognizes them as edible. Of course you'll feel better if you stop eating that kind of crap. Being gluten free forces you to read the label of everything you buy, which is a great idea. Avoiding something like gluten or sugar or dairy that's in a lot of processed foods will prevent you from eating those processed foods, and you'll feel better. It doesn't really matter what you avoid, as long as it prevents you from eating things your body doesn't consider food. If you want to be gluten free, or vegan, or whatever, just make sure that the restriction isn't causing you to eat more processed foods. Buying gluten free macaroni with soy cheese is not healthier than regular macaroni and cheese. In many cases it's worse, because removing the gluten (or turning soy beans into something that could pass for cheese) means even more processing, and your body really has no idea what you're eating. The same goes for commercially produced gluten free bread: if it tastes like wheat bread but isn't, think about how many chemicals are required to make that happen.
Between the development of agriculture and the development of capitalism, we have done some very strange things to our food. If you're feeling totally overwhelmed with the variety of diets, health scares, additives, and allergies, start by taking a deep breath. Even if you already have diabetes or high cholesterol, it's not too late to start eating well. Part 2 of this topic will talk about what "eating well" actually means, and where to start.
In the meantime, here's a link to an interview with Michael Pollan talking about his new book Cooked, which I definitely recommend: https://soundcloud.com/inquiringminds/17-michael-pollan-the-science_of_eating_well/s-VpTd6 There's another interview first, which is also interesting, and the Michael Pollan interview starts at 13:30.