Pregnancy is a time when some women feel that they have earned their licences to eat as much as they please. They even have their spouses taking 'craving requests' and trying to satisfy their changing dietary needs.

There are other women, however, who will go to great length to avoid gaining weight. There are women who use purging agents, go on crash diets and turbo- charged physical-activity programmes to get back to their figure in record time after delivery.

All of these actions can put both mother and foetus at risk, preventing inadequate amounts of calories and nutrients for development and the important fat stores necessary to sustain lactation. With this said, I am in no way advocating uncontrolled weight gain, as this also has several risks, including birth injury for the infant. Women who gain excessive weight may have babies who are too large for normal vaginal delivery and will require a Caesarean section.

Guidelines have always existed for the healthy margin of weight gain recommended for a woman, depending on her pre-pregnancy weight. This is based on whether she was underweight, normal weight or overweight pre pregnancy.

During pregnancy, the increased caloric need is not a lot and is only necessary in the second and third trimesters and is based not only on energy, but on a healthy mix of nutrients to sustain the mother's and foetus' nutritional status.

There is a new guideline put out by the Institute of Medicine in the United States which is similar to its 1990 guideline, except for the obese category.

Another study published in the Journal of the National Medical Association found that obese women can sustain a healthy pregnancy without gaining weight; this can be achieved with supervision from a medical team while maintaining a balanced nutritious diet.

Most women will only need an extra 300 calories per day in the second and third trimesters to maintain a healthy pregnancy and this can be consumed from a wide variety of foods from the six food groups. During lactation, the caloric need will increase to approximately 500 calories extra each day.

Example of 300 additional calories:

1 slice wholewheat bread - 70 calories

0.5 ounce cheese - 50 calories

8oz 1 per cent milk - 102 calories

Lettuce and tomatoes - 10 calories

1 small mango (4oz flesh) - 60 calories

6 small cream crackers - 70 calories

1 tbsp peanut butter - 100 calories

8oz soy drink - 80 calories.

Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email: yourhealth@gleanerjm.com.