Once i get pregnant, when do i need to start watching my diet?

Immediately: You should avoid starches unless you exercise a great deal. Avoid deep sea fish, such as yellow fin tuna, shark, etc. Avoid raw meats, such as sushi. Stress fruits and vegetables, and try small, frequent meals.

Yes, stops wt gain: You should be watching your diet even before you get pregnant regarding your weight and eating healthy foods, avoiding sugars, fast food etc. Once pregnant the goal is to eat healthy esp. Proteins, fruits and vegetables and not gain too much, but its not the time for weight loss or dieting.