Pregnancy is not a time to restrict calories, nor is it a time to literally “eat for two!”
The general recommendation is to add about 0-100 kcalories per day in your 1st trimester, about 340 kcalories per day in your 2nd trimester, and finally 450 kcalories in your 3rd trimester. [It may be easier to leave out the kilo part of calories as many of us are used to seeing just calories.] This can be achieved by, for example, drinking a pint of low fat milk, or eating a peanut butter sandwich on whole brain bread.
This is also not a time to lose weight. Steady, but healthy, weight gain is expected with an average of between 25-35 lbs (11 to 16 kg) from your starting weight if you weight at conception is normal (BMI of 18.5 to 24.9).
The amount of weight you should gain will depend upon your pre-pregnancy weight and height. You should gain 1 to 5 pounds (0.5 to 2.3 kg) in the first trimester and about 1 pound (0.5 kg) per week for the rest of your pregnancy. Note that your weight gain will often be irregular from week to week.
The average breakdown of total weight gained is:
- Baby 7-1/2 lbs (3.5 kg)
- Your breasts — 2 lbs (0.9 kg)
- Your protein & fat stores — 7 lbs (3.2 kg)
- Placenta — 1-1/2 lbs (0.7 kg)
- Uterus — 2 lbs (0.9 kg)
- Amniotic fluid — 2 lbs (0.9 kg)
- Your blood — 4 lbs (1.8 kg)
- Your body fluids — 4 lbs (1.8 kg)
Your expected weight gain will be different if you are underweight or overweight at conception. If you are underweight at conception (BMI of below 18.5), you should try to gain 25 to 40 lbs (11 to 18 kg) during your whole pregnancy, gaining 1 to 5 lbs (0.5 to 2.3 kg) in the first trimester and about 1 lb (0.5 kg) per week for the rest of your pregnancy.
If you are overweight at conception (BMI of 25 to 29.9), you should gain 15 to 25 lbs (6.8 to 11 kg) during your pregnancy, gaining 1 to 5 pounds (0.5 to 2.3 kg) in the first trimester and about half a pound (0.25 kg) per week for the rest of your pregnancy.