As an example, he pointed out that while the pyramid recommends 6 to 11 servings of grains, it doesn't explain that the number of servings isn't a matter of personal choice; rather, it depends upon the different caloric needs of individuals. (articles.chicagotribune.com)
Just like everyone has different caloric needs, a person's water intake is affected by age, weight, activity level, and environment. (health.com)
We all require different amounts of energy and have different caloric needs. (anymanfitness.com)