On a 1500 cal diet to lose weight. been very hungry and lightheaded. what can i do to adjust and lesson side effects? i used to eat very junky all day so this is a big change?

It is not just about the quantity (calories) it is also about the QUALITY of what is eaten. Carbs last as a fuel source for 60-120 minutes depending on the fiber content. Protein lasts up to 8 hours as a fuel source. Increasing the proportion of protein at each meal will keep an individual full. A healthy individual should consume 0.5 - 1.0 grams per ideal weight (150 lbs should get 150 gms/day)