The basic theory is that your body prefers to be slightly alkaline rather than acidic. Now I'm not going over board on it, but concentrating on improving my body's alkalinity and keeping a healthier balance. It's all about balance. You shouldn't stray more one way than the other. However it has meant a big reduction in red meat for me, which I've actually been fine with, though even fish is slightly acidic, but not as much as red meat. However, this is a balance, besides I've just had a steak - there's no denying that the nutritional contents of good quality meat is always going to be beneficial for bodybuilding, size and strength. You can't lean out a prop, or a strong man, it's pointless. It's about tailoring it to suit your lifestyle, goals and requirements.
There's lots of interesting articles on there, some to be taken with a pinch of salt, some to be read with interest. I'm not one to tell you which is right or wrong, however read some of these and make up your own mind.
http://www.sethigherstandards.com/energize-your-life-by-alkalizing-your-body/
http://articlesofhealth.blogspot.com/
http://www.bodybuilding.com/fun/acid_alkaline_imbalance.htm
What is being made clear as a point is that eating green based vegetables, and increasing your vegetable and non animal protein is sensible and a good way of keeping your body better balanced. Of course your body balances itself, but if you can help it more by changing your diet so much the better? So many people eat stacks and stacks of red meat without really thinking about how it affects their body. Now don't get me wrong, a balanced diet is perfect and you shouldn't need to change anything. But in this game we're pushing ourselves and want our bodies to respond, so we become slightly extreme and often go OTT, and forget the importance of "balance".
Simple things like bicarb, or the lemon drink water is a good way of boosting alkalinity. Especially if you've had an animal rich based food. Hitting things like 9 fruit/veg per day is conducive to redressing the balance if you eat lots of animal proteins. Things like greens drinks, and a highly alkalising foods allows for optimum clearance of toxins and encouraging cellular health (and as a result better synthesis and cellular activity within the body.)
Don't take this as, become a vegan/vegetarian, it's not necessary, however think about the ratio of meat to alkaline foods you consume.
I think it's interesting, and whilst I'm not living by it word for word, it's definitely got me considering a more careful approach to keeping my feeding sensible and more conscientious.
I've had a definite improvement in my eczema while using it and read anecdotal reports of it helping psoriasis and acne, but your mileage may vary.
