Daily calories and exercise

Assuming your logging is otherwise accurate, MFP intends you to eat back all exercise calories. However, that is a big assumption.

To be sure your logging is as accurate as possible:
1) make sure you are using a food scale to weigh ALL food. Do not use measuring cups or spoons; do not enter anything as "1 serving," "1 piece," etc.
2) make sure your calorie burn numbers are reasonable. If you're using the MFP exercise calorie database, many people find those estimates to be too high, so they begin by eating only half the estimated exercise calories.
3) be consistent and patient. If you do both 1 and 2, you may still not see the scale go down for several weeks because you don't have much to lose, and your weight loss will therefore be slow.

Here's the upshot of it all: the theory behind "net-calories" as used by MFP and others.

1. You've got a "basal metabolic rate", or BMR. There are calculators all over the web where you can figure out what it is. It's how much energy (i.e. calories) your body needs to burn (whether in food or stored fat) to perform all the routine metabolic processes like pumping blood, digesting food, and thinking. It's based on your gender, height, weight, and age. So, for instance, a 35 year old dude who's 6' tall and 220 lbs might have a BMR of around 2,500 cals/day. But a 50 year old female, 5'6 and 140 lbs, might be more like 1600. I'm making those #'s up because I don't have a BMR calculator on screen, but that's the gist of it. Go find out what your BMR is. Your BMR is the # of cals you can eat per day and break even, without exercising at all, just sleeping and watching TV and sitting at a computer and the like.

2. Let's say your BMR is 1,900 - a pretty typical number. Now, let's say today you do 300 calories worth of exercise. Well, instead of burning 1900 calories, you're obviously going to burn 2200 calories today. So that's how many calories you can eat and still break even. Anything LESS than 2,200 and you're losing weight. Anything more than 2,200 and you are gaining weight. So, exercise calories + BMR = your break-even intake for the day.

3. A pound of body fat contains 3,500 calories worth of energy. So, if you eat 350 less calories than your break-even caloric intake (BMR + any exercise you do), you will lose 0.1 pounds of fat. If you eat 700 less calories you'll lose 0.2 pounds. And so on.

So from this, you can decide how many calories to eat per day. To lose a pound per week, you must be, on average, 500 calories under your exercise-adjusted BMR, because 500 cals x 7 days = 3,500, or loss of one pound. Similarly, if you manage to be 1,000 cals per day under your exercise-adjusted BMR, which is pretty challenging, you'd lose 2 pounds.

MFP asks you the questions it needs to determine your BMR and is simply applying this math each day in the background. You can do the math yourself, as described above, to set your calorie goal.

Two caveats:

A. In reality, exercise calories are not as high as exercise machines or most apps tell you. Why? Well, let's say your BMR is 2,400 (high if you're a woman, but just go with it for a moment). That means you are burning 100 calories per hour over a 24 hour period ... doing absolutely nothing. You can sleep, or watch TV, and still burn your 100 cals/hour. Now, let's say you go for a one hour walk and some app tells you you just burned 300 calories. Fine, except you would've burned 100 anyway. So you really only got 200 additional calories of fat burn. For this reason, exercise calories tend to predict more weight loss than actually occurs. In other words, the "net calories" concept is not perfect. You are better off just figuring out your BMR, figuring out how much weight you want to lose per week, and working out your target caloric intake, irrespective of exercise. If you do that, the exercise becomes a nice little extra, instead of being baked into a formula that overestimates how much weight you will lose.

B. I've learned from my own dieting efforts that weight loss is not linear but always works out in the long term. If you eat the correct # of calories to lose 1.5 lbs/week, you will lose 1.5 lbs per week in the long run, but you can have days, or weeks, where seemingly no weight is being lost. Why this is, is a great mystery. The "plateau". Every person on every diet eventually experiences it. The thing is, if you just plug away and record every single damn calorie and hit your targets religiously, you will lose the weight. It may be stubborn for three weeks and then shed off you like butter melting in a hot pan. It always works out to the BMR formula in the long term. You have to learn to ignore the daily ups and downs of the scale.

I once went on a diet and lost 50 lbs and tracked every single thing I put in my mouth for 4 months, and every minute of exercise. My weight loss over 4 months mapped precisely, to within half a pound over a 50 lbs weight loss, to the formula described above ... and as used by MFP (I don't actually know what MFP's algorithm is, but it's gonna be something liked I've described). Note, I deducted 20 % of the supposed exercise calories from various cardio machines, and that got the formula to line up with my actual weight loss.

Hope that's helpful.

lgfrie wrote: »

sijomial - I'm not sure we're saying anything different. Although, looking at your profile pic vs mine, I'm inclined to assume you, not me, are correct in these matters LOL

If your BMR is 1,900 and you do absolutely nothing that day but sleep and watch TV, isn't it true that you can eat 1,900 and "break even"? Then if you turn off the TV and go do some exercise, your break-even point will adjust upward to account for the exercise performed. So, 1/2 hr on an exercise bike, and perhaps you're then at 2,200 instead of 1,900. The 1,900 is what you get just for remaining alive for the day - breathing, thinking, digesting food, etc. To break even at a caloric intake over 1,900, you have to go work for it - that is to say, exercise. I believe we are both saying that.

No, that is not true. BMR (basal metabolic rate) is the energy required only for your basic life functions. It is what you'd burn if you were in a coma. If you are awake, sitting, thinking, walking even from the bed to the toilet and back, etc., then your calorie burn is more than your BMR.

There is also a resting metabolic rate (RMR) calculation, which is closer to what you're describing, but even that measurement requires fasting (i.e., does not take into account digestion), avoidance of mental stimulation (i.e., takes into account consciousness but not much additional brain activity), complete physical stillness (i.e., you're not even picking up the TV remote)...you get the idea. https://en.wikipedia.org/wiki/Resting_metabolic_rate#Clinical_guidelines_for_conditions_of_resting_measurements

BMR is in that respect a theoretical concept that has limited application to daily life. The vast majority of us burn more calories than our BMR even if we are completely bedridden. You therefore "break even" at a higher calorie intake than your BMR even with minimal physical activity.