burn 800-4000 calories per day, how much should I eat?

Your HRM is wrong.

What brand is it?

If not Polar - did you input age, gender, weight at minimum?

By the way, keep this mantra in mind.

Diet is for fat loss.
Exercise is for body shaping and heart health. it can help or hinder fat loss.

If you want to exercise that much that often - you would be better served eating at maintenance level, and just let your exercise create the deficit.

So go back to diet/fitness profile, change activity level to whatever is true for your non-exercise time.
Set goal to Maintain.

Exercise away!

Your BMR and TDEE are very different. TDEE takes into account your daily activities, while BMR is what your body needs just to survive (pump blood, respire, etc). You need those calories; if you are eating 2000 calories a day and burning 3000, you may think your body will begin to break down fat. You would be wrong. The first thing your body uses when it isn't getting enough fuel is muscle. When your muscles begin to break down, not only does your metabolism slow, but you have to keep in mind that your heart is also a muscle. If your body begins to break it down as well, you are surely in some trouble.

Wow, that surely would be some trouble. Hmmmm.. If what you are saying is true then I will have no problem getting the extra calories. I will just juice more fruits and veggies. Luckily the protein shake gives me some added calories after each workout.

So if I burn 3000 calories per day and my fitness pal says that I should eat only 1870 to lose 2lbs per week, I should eat 3000 more calories? I was thinking about bringing the number to 1600 calories and then replace what I burn. Are you saying that would be a good strategy for losing the most weight possible? I really enjoy the physical activity and have no problem whatsoever doing the work.

Sounds like you're looking for a quick weight loss solution, those fail. Yes it's true you will burn away at muscle if you don't consume enough food. Which will lower your metabolic rate, slowing down your metabolism and will just continue the downward cycle.

I think you're missing the point, "drinking more juice" isn't the answer. Juice "CAN" be a "PART" of a well balanced diet, assuming it's juiced through a juicer, and not sugary fruit juices.

If it's true what you said "i like the exercises i do." Then what's the problem with eating up your food? If you're not going for a quick weight loss method?

Here is why quick weight loss methods don't work. First off, already mentioned the metabolic issues by not eating enough and loss of muscle mass, 2nd your thyroid will slow down also slowing down your metabolic rate.

Another big reason these fail is due to the fact of you're just not adapted to it. Someone just doesn't wake up one morning and go run a marathon, you have to develop the skills to finish the marathon. This marathon is your goal weight. You need practice, in making right food choices, exercising properly, doing what you need to lose your weight. Sure you can go balls to the wall and lose weight quickly, but you will burn out, and crash and gain the weight back. You also didn't develop the habits necessary to keep the weight off. If someone loses 20lbs in 1 month, and another person does it in 6 months, the person who done it in 6 months has a lot more practice than the person who did it in one month.

What kind of exercising are you doing that burns 3000 calories per day???? I have never seen numbers like that before!

^^^^^^^^ *sits and waits patiently*

hilarious!!!!

There's really no reason to be doing that amount of exercise to lose weight. You could more easily do it by just eating fewer calories. But, to each his own.

You should never be netting below your bmr. Either start eating more calorie-dense foods, or exercise less. Your body won't last long if you put that much strain on it; it's like trying to make a car run with no gas.

If I don't eat below my BMR how can I lose weight? My BMR may be around 2200 or so and MFP says to eat 1870 or less to lose 2lbs per week.

Wouldnt my body just use the stored fat as energy?

How come the people on biggest loser are exercising a ton and not eating more to compensate for the calories they burned?

*so confused*

Your BMR is based on how many calories you would burn if you did literally nothing all day. If you aren't eating at least that number... you aren't supplying your body with what it needs for its essential functions... So when you are burning more than you eat your aren't doing your body a bit of good. EAT MORE FOOD. or you know... work out less. the choice is yours.

let's put it this way...if you eat 2000 calories and burn 2000 calories in a day, your body will have ZERO fuel, because the exercise negated what you ate. SO if you're eating 2000 calories and burn 4000, you're body is getting NEGATIVE 2000 calories for fuel. Imagine it's a car instead of a body...could it run on -$40 of gas? No, it can't. And neither can you. If eating 3500 calories or more seems like too much to you, then you need to exercise less, simple as that. Find a balance that does work for you. Your numbers at the end of the day should NEVER be a negative, and really shouldn't be under your BMR.

I bought a heartrate monitor and people say its probably about 90% accurate. I go to LA Boxing and each hour session I do burns 800-1000 calories. I am soaked in sweat every time and I am hooked. I sometimes do 4 classes per day no problem. Usually I do 2-3 classes per day. Certain light days(1x per week) I will only do 1. I drink plenty of water and get the proper protein after each class.

I suggest you read this article: http://www.bodyrecomposition.com/fat-loss/exercise-and-weightfat-loss-part-1.html
You're not burning 800-1000 calories per hour session. Why are you doing 2-4 classes per day anyways?

I read part 1 of the link you posted and I understand what it is saying. It is saying that it is unrealistic for people to have the time or motivation to do such intense excercise, but exercise at greater levels has shown to have more of an effect on weight loss.

I have no problem doing 2-4 classes per day and look forward to getting to a point where I can maintain and maybe only work out 1 hour per day, 6x per week.

i am burning 800-1000 calories per session. I have a polar HRM and it has my height, gender, and weight in there. Trust me, the workouts that I am doing are like NOTHING else around. It is more intense than racketball, swimming, basketball, and anything else you can think of. it goes from punch/kick combos to jumping jacks, pushups, burpies, squat jumps, back to punch/kick combos NONSTOP for an hour. I know it doesnt seem possible to burn that many calories per hour but it is.

What were you getting at though? I know I can probably turn it down a little in the exercise department. My diet is pretty good though, no fast food, little processed food, no pop and many fruits and veggies. I could go into more detail but I was just wondering what you wanted me to discover in the article. It was a very intersting one btw!

seriously, i would keep doing what your doing, it may take a couple of weeks or a month or 2, but you will hit the wall or plateau like everyone talks about, when that happens make some changes. go after it man knock the pounds off. you can do it.

*sniff sniff*
I smell a troll.

I came to the same conclusion.