The nutritional and metabolic environment of the fetus as comprised by the mother has great impact on the baby’s later development. If the fetus is exposed to high blood sugar in utero, the DNA of the fetus is geared to anticipate a similar environment following birth. This can lead to health problems.
The best guideline for the amount of calories needed during pregnancy is to eat for 1.1 during pregnancy. This is because the fetus needs 10% of what mom needs. The additional nutritional needs are the supplementation of vitamins, calcium, iron, zinc and DHA. Eating for more than 1.1 is a common problem and leads to problems.
Being physically fit and active is especially important during pregnancy. Exercise in moderation is beneficial in most pregnancies. This should be evaluated and decided by your obstetrician.