Q: I eat tuna and veggies for lunch. 90 calories, 19g protein, 2g fat and 0 carbs in a 100g serving. What do you think?

A: The main concern about tuna is mercury contamination. Check out www.oceansalive.org for data on various types. Skipjack, the variety that makes up most "light" tuna, is OK, but bluefin and yellowfin are on the "health concern" list.

I want to ask you to look at a different number, rather than the protein, fat and carbs per weight of food. Here's the formula, devised by Dr. Joel Fuhrman:

H = N/C

H is the health value of the food. N is the amount of nutrients, and C is the number of calories. Simply stated, the healthiest foods provide the greatest concentration of nutrients in the fewest number of calories.

Protein, fat and carbs are macronutrients. That's where the calories come from - those three sources. All the other things our bodies need - water, fiber, vitamins, phytochemicals by the thousands - should be injested in as few calories as possible. That's how we live healthy. That's how we achieve our right weight. Whole plant foods offer the highest concentration of nutrients per calorie compared to animal products and processed foods.