It may seem that a tiny baby needs very few calories each day, but with their bodies growing drastically in the first year, it's important to make sure your infant is receiving plenty of calories from food sources you've discussed with your doctor.
Calorie needs by age
Infants need a relatively high number of calories for their body weight compared to older children and adults. According to Merck, healthy infants under six month of age need about 50 to 55 calories per pound of body weight. From six months to one year, babies need about 45 calories per pound of body weight.
Although newborns may lose weight in the first few days of life, they should regain their birth weight by the time they are two weeks old. By six months, babies should weigh roughly double their birth weight.
The National Academy of Sciences recommends that 50 percent of calories come from fat for babies six months and under. From seven to 12 months, 35 percent to 40 percent of calories should come from fat.