Dietary fats are important because they are the ones that produce  energy for the body. Fats should be monitored since excessive fats  can be risky for your health.
Age last birthday: One method of insurance rating which rates people a their age as of their last birthday, with such rating held until the next birthday. If your policy is approved at your current age (prior to your next birthday), you will be rated at your current age (as opposed to age nearest birthday).
Meaning childish adult person is from c.1600. Meaning youngest of a group is from 1897. As a term of endearment for one's lover it is attested perhaps as early as 1839, certainly by 1901; its popularity perhaps boosted by baby vamp a popular girl, student slang from c.1922. As an adjective, by 1750. Baby food is from 1833.