Suggest why carbohydrates such as bread should be wholegrain if possible.

Carbohydrates are in everything, they are an essential energy in the Human Body

So your best guess/answer should be that you can switch to wholegrain, and in other words. This is basically things like Wheat bread.

Explanation:

And here's your why. The less carbohydrates you consume, the less you have to worry about excessive weight loss.