Is this advisable?

I'm no expert but when I'm feeling light headed and dizzy its usually because I didn't eat enough and that's just my body's way of telling me "yo homie you need to eat something. our blood sugar levels are too low and we about to pass out to protect yoself from over exerting yourself."

As for feeling guilty about eating those calories don't. Apparently you need to eat something like 3500 calories to gain a lb of fat or something. If you're eating at maintenance you're going to lose weight since your exercising and burning off calories.

And sleep more. About 8-10 hours a night if you can. It sounds stupid but it helps.

I've decided to do 30 day shred workout and did Day 1 just earlier this morning. It was just right after I came home from work (I do night shifts). I didnt eat since Midnight (7 hour gap) and after doing the workout i was feeling a bit lightheaded and maybe a little dizzy. So I decided to eat the remaining < 300 Cals from my diet with a simple Mango (207 cal) and slept about 3 hours after that.

For anyone who is experienced is this good enough? I'm worried that I'm doing something wrong plus I get a bit guilty eating right after the work-out since i feel like I just cancelled all the Calories that I just burned.

MFP is designed so you eat back your exercise calories - think of it as fueling your workouts.

When you plugged your data into MFP - it gave you a calorie deficit BEFORE exercise. So, when you exercise you make the deficit larger. When the calorie deficit is too large - you are actually "burning" off muscle along with fat. Moderate deficits help you maintain muscle & lose fat.

Light headed - either your calories are too low - or your macros could be better. Make sure you are getting enough protien & healthy fats.

The time of day you eat will not be an issue.

Try eating before the workout. Eating your left over calories does not cancel out your workout. You eating at a deficit takes care of the weight loss. You working out is for strength, lean muscle, and overall health.

Look at it like this: if your blood is in your digestive tract making use of lunch then you might feel a little weaker in the extremities (think if that "don't swim for an hour after eating" homily; there is some sense to it because you are a little weaker.) If you don't have fuel in your blood (oxygen and glucose) you may feel weaker. Eating right after exercise causes some people to feel nauseated because the blood is busy elsewhere. Eating right before exercise may lead to a sensation of heaviness in the gut because you are, well, a little heavier in the gut while digestion gets things moving along. Time of eating is not as critical as the overall quantity of food you take in. And it's not like ALL your blood takes off to your nether parts and leaves you standing there limply sogging to the floor......

I read something the other day that said there was no proof whatsoever that eight glasses of water was mandated, but there was definite evidence that if you are thirsty then you should drink because thirst is a sign of dehydration. Common sense will rule the day. Look for long-haul improvements a step at a time....baby steps will do it just fine.