I read the book in one sitting, and I think the message in it is great! I recommend it to anyone who feels sluggish, depressed, and/or overweight, because it might be the secret to make you feel better.
I'm one of those people who's pretty much obsessed with eating only healthy foods anyway--- eating fresh fruits and veggies and whole grains, eating natural and organic whenever I can, staying away from too much sugar and salt, and avoiding processed, hydrogenated, and deep fried foods at all costs. I've found that I feel GREAT -- I have so much more energy, I don't get hungry as much, and on top of that I look so much better and healthier and I stay thin. (Part of my obsession started when I became friends with a nutrition major a few years ago!) I too used to eat all the "wrong" foods myself once, and I really did feel sluggish alot, and I gained weight my first year of college.
So, from someone who's had firsthand experience about switching to a completely healthy diet, I can say that Dr. McKeith's advice about eating fresh, unprocessed foods is excellent. She also tells you which foods to avoid and what foods are making you fat and feeling depressed, which can be a real eye opener.
I also like the way she analyzes a woman's diet who's depressed and can't seem to lose weight, because you can see how little nutrients she's getting (coffee with sugar and a bag of digestive biscuits and 2 bags of crisps for lunch, for example) so her body just hoards whatever it gets and she just feels miserable.
She does go into graphic detail at times, but I think it's good if you're looking for a wakeup call as to what your diet is really doing to you.
The only problems with the book, I think, are all the kinds of exotic foods she mentions to eat regularly (where the hell am I supposed to find all those exotic types of seaweed, for example?) And the food combinations...that's just a little bit obsessive. So I wouldn't say follow everything in it religiously.
But overall, it has a great message.... AND IT WORKS!