Gained 6 lbs in ONE day!!?? why.....

6 pounds in one day is clearly water weight. There is no way you have gained six pounds of fat in a day. When you're doing a lot of working out, you may gain a bit due to muscle, but I wouldn't think six pounds.

I am guilty of weighing too often, about twice a week. And I really grab the tape measure too often. In fact, I've given it to my husband with instructions to hide it and not let me have it for 3 weeks. Just keep doing what you're doing and know that in a month, it's going to average out

Id say water weight.

I agree with ninerbluff about the under-eating. I know you're eager to lose weight, but you still have time, and it's only going to be effective if you do it in a healthy way. If you keep at a lower calorie that your body needs, the cravings will become unbearable. Believe me, been there, done that. And you'll only feel worse once you eventually indulge.

Not to mention the stress it puts on your body. Calories, carbs...it's all converted into energy your body needs. If the body does not get enough energy from the food you eat, it does start to eat at the fats first. But after continual strain, it starts to take energy from muscle tissues. While this is going on, there is considerable strain on the various systems of the body as they must try to maintain their functions with minimal energy. That's known as survival mode. Worst case scenario, if you keep doing what you're doing, by June you might be in the hospital dealing with the effects of an eating disorder.

You're young, don't fret too much about the weight. Remember, it's more about healthy living than about weight loss. Don't let weight loss be your primary motivation to eat healthy and exercise. As my Physiology teacher told our class, do it because you want lots of energy, you want your skin to look great, and your hair to shine, and to feel good about yourself, and to challenge yourself.

The reason the MFP tells you to eat more when you work out is simple:

Your food goal is 1200cal daily (that's probably way too low, but we won't get into that now). Now, if you eat 1200 cal on, let's say monday, and do cardio and burn 500 cal, then you really only ate 700cal that day. Why? Because those 1200 cal are calculated from your average daily activity (how much you move at school/work etc). So if you work out on top of that, you're burning much more, and need to supplement with more food to fill in the gap from 700 to 1200.

If you don't eat back your calories, your metabolism will slow down, and weight loss will take longer! I know it sounds strange, but it's fact! Don't make the mistake of undereating, it will kill your results!

Actually, I'l amend my previous statement. When you build muscle your body begins to burn more calories, so, to a certain degree, we do exercise to lose more weight. HOWEVER, you must EAT the proper amount in order to develop new muscle and in turn rev up that metabolism. It might seem backwards because of the nonsense us girls are taught about eating like birds to stay slim, but it's the truth!

The Beachbody programs usually require you to eat quite abit to keep up metabolically with their advanced programs. 1200 seems abit low for any Beachbody program, let alone the much lauded P90X (I'm currently on Insanity). I do have the dvds and nutrition guide and quick looky-loo show some calculations. Did you use them when determining how much to eat?

Cause 1200 is just too low for advanced workout programs, period.

Did you need a Pooh?

Because you weighed yourself at night and havent properly digested or pooped it out yet. Its the weight of what you ate.

Stop weighing yourself so much. Pick a day and weigh yourself first thing in the morning on that day every week. Your weight will fluctuate (as you noticed) throughout day so it's not really a very good metric. Instead, take your measurements and track those, they tend to be a better gauge of your progress. Who cares what the scale says as long as your body looks the way you want it to?

It is normal for a persons weight to fluctuate like that from morning to night, I had to do my best to only weight myself first thing in the morning because that is your "true weight" if I do weight myself again at the end of the day i can be almost 4-5 pounds heavier. and before my friend taking a human kinetics course in university told me about the fluctuation I would get really discouraged but it was always so much better in the morning.