Calcium does increase metabolism. And dairy is considered the best source because the body absorbs more of the calcium from dairy products than something like spinach. I've read that healthy people absorb only about 20-35% of the calcium from dairy products and from other foods, it's even less. Studies have also shown that calcium absorption is also not as good in foods fortified with calcium. That includes soymilk for which calcium is 25% less bioavailable compared to that in dairy foods. 1 cup of low fat milk has 300mgs of calcium, 1 cup of non fat yogurt has 400mgs, and 1 cup of non fat cottage cheese has 400mgs. But there's a downside too so you have to find a balance. Dairy is the best source of calcium, but the dairy industry pumps all kinds of junk into cows and it ends up in the finished product. Plus something like cottage cheese is loaded with sodium. These days, I'll eat nonfat yogurt cause it's high in calcium, high in potassium, low in sodium, low in fat, and low in calories. But that's about it as far as dairy is concerned.