Mark Bittman is one of the greatest cooking writers ever. He's a weekly columnist for the New York Times, but I know him best and originally as the author of the amazing How to Cook Everything. How to Cook Everything basically taught me how to cook. In it, he runs through everything from the very basics of how to stock a kitchen and how to cut vegetables to how to prepare complex roasts, full dinners, and more. Pretty close to anything you'd want a recipe for is in there, except pasta salad which he seems to think is an abomination and forbids you from ever preparing. The writing style is plain and accessible, and its a book I recommend to anyone looking to learn how to cook or who wants a great omnibus of recipes available.
Food Matters, on the other hand, is a bit of a different beast. It has a few recipes, about 75, that focus mostly on very basic cooking--preparing cooked beans, grains, boiled and steamed veggies, simple sauces, and then a few dozen recipes for each meal that tend toward simple combination of the basics that can be rapidly prepared. The focus of the recipes is on things that can be prepared quickly and/or in bulk that are composed primarily of complex carbohydrates, fresh fruits and vegetables, and very small amounts of meat and dairy.
The reason for this strange set of recipes is explained in the first half of the book. Bittman appeared on the Colbert Report a last year to discuss this philosophy. Basically his food consumption ideas aren't new, but focus on the "vegan until 6pm" and "only eat foods with less than four ingredients" ideas. His book focuses on showing you you can eat a diet that is very high in vegetables and complex carbohydrates and very low in animal products and processed food with minimal effort, and still produce satisfying food quickly. His points are that our current diet cuases health problems ranging from heart disease to diabetes to obesity, and that this is due both to high calorie, low nutrition foods (chips and MacDonald's and Twinkies) and to too large a proportion of our diet being high fat animal products. This diet is also awful environmentally in terms of both energy consumption and waste production, pointing out not only the old standard of lb of meat taking a dozen or so pounds of grain to produce, but that all these processed foods and factory farmed meat take a huge amount of petroleum and energy to make. Eating like "food matters" allows you to both improve your health, lower your risk of long term diseases, and lose weight, all while helping the environment.
I do have a few major issues with the philosophy portion of the book. Bittman seems to have a problem with low carb, high protein diets that's based more in his anti-meat environmentalism than in actual fact. I myself gave a low carb diet a try over the last year (specifically the Men's Health TNT Diet) and lost weight, gained muscle, and my cholesterol dropped 15% (and the good went up as the bas went down.) I've since adapted to a more sustainable some-carb diet, and gained back a bit of weight but overall feel pretty good. The advantage to a high protein diet is that protein and fat, while high caloric density, have a high satiety factor, so a couple strips of bacon or a couple eggs in the morning leave me feeling full until early afternoon, while a couple donuts leave me hungry again almost right away.
Epidemiology on diet is very difficult, and lab results don't always translate into real world results. This was the major flaw in low-fat diets--that and that the whoel fat reduction then "bad fat" reduction would reduce cholesterol and thus heart disease was a (reasonable) deduction based on the observation that heart disease is correlated with high cholesterol. Except it turns out that most cholesterol is synthesized by the body, not absorbed from food, that lowering cholesterol intake doesn't tend to have that much of an effect on blood cholesterol, and that cholesterol is correlated with heart disease, but not causative (see Vioxx, which lowered cholesterol but not heart disease and increased stroke risk).
However, recent meta reviews show that, in fact, high protein low carb diets work better than anything else in reducing cholesterol and weight up to one year. Bittman addresses this in his book, but dismisses these results with a well, i'm sure it has long term negative effect stance with no evidence to back it up. Further, he does this immediately after he basically mocks people who dismissed the results of a study that showed low fat diets don't improve health on the evidence-free assumption that everyone on the diet cheated. It is very intellectually disingenuous, and when he dismisses studies that don't support his worldview it heavily undermines his criticism of others.
He also, almost randomly, rails agains the pharmaceutical industry and its "scientist for hire." Which, as one of those people who do science in exchange for a paycheck, I found more than a little insulting. The insinuation was that none of us industry scientists can be trusted cause our sinister bosses pay us and demand we thus falsify results. I at least consider myself a moral and ethical person. Also, there are a lot of good things to come out of the pharmaceutical industry...and also also, I have no idea why he kept ranting about pharmaceutical companies in a book about food, except that he was somehow lumping together government agencies, the food industry and the pharmaceutical industry into one big pile of evil corporatism that is destroying America's health. I found the screed parts of the book to detract greatly from his very good points about the health and environmental impact of the way we currently eat, and could turn a lot of people off to that message.
Overall I wish he had been more neutral, and less dismissive of studies that contradicted his viewpoints. I do like the recipes and the practical tips on cooking and eating right, and have integrated some this into my current diet. Bittman agrees with the low-carb folks that veggies and complex carbohydrates (whole grains) are better than high starch foods are better than high sugar foods are better than processed, sugar added foods. They mostly disagree on the relative proportions of complex carbs vs protein. Bitmman's tips on bulk preparation, what can be frozen and how to eat well while working full time are definitely worth it, and his views are interesting (if occasionally offensive) to read. But I can guarantee I'll be going to How to Cook Everything a lot more often than Food Matters.