Lots of people are intolerant to cow's milk without realising it. Symptoms include excessive mucus, headaches, asthma, and eczema. Cow's milk has also been linked to insulin-dependent diabetes.

There is no such thing as a healthy diet that suits everyone. We know different societies do well on different foods. The same is true if individuals. No two people have the same DNA, so why should they have the same nutritional requirements? Popular wisdom holds that red meat and high-fat diets are bad for us. It's not true. Any food can be good or bad depending on your metabolic type.