Hard boiled eggs is a good alternative to other foods that we normally eat. One large hard boiled egg contains 78 calories , so if you eat too you just multiply it. If you eat meal, it could contains more than 300 calories depending on the food you choose. On a personal note, I survived eating 2 hard boiled eggs when I was dieting before. However, it fails to give me sufficient energy to welcome a very stressful day. I always get tired when I am about to start a work. I also walk slowly and I think my brain is working slowly as well. It could help in maintaining a good diet to lose weight, in fact, there is this Military diet that if you try to eat eggs alone, after 3 days, you could lose 2 lbs. It really works on some but not on some who have health issues. I suggest you ask your dietician before starting this diet.