The 3500 calorie equation must be flawed.

angiechimpanzee

I'm convinced it must be much more complicated than "create a deficit of 500c a day and lose a pound a week".

The reason I say this is because I've seen far too many people on this forum doing just that and losing nothing sometimes, & I've seen people doing that & losing multiple pounds at a time. There's gotta be other factors. Otherwise, eating less would ALWAYS yield faster results, and eating more would ALWAYS yield slower results. I think that every person has a certain threshold of calories they must stay in between in order to burn an optimal amount of weight. That "for every 3500 calorie deficit, a pound is lost" equation is a good guideline but I don't think the body actually works that way. Otherwise how do you explain all the variability in results?

yarwell

Certainly is. The various bodyweight simulators tend to give a loss rate more like 0.8 lbs/week for an initial deficit of 500 calories, and that declines with time.

Then as you say there are the "stalled" people, with little in the way of reliable evidence about what's going on there.

bpotts44

Day to day changes are more due to water than anything. Best bet is to eat at a certain caloric level or plan and then adjust from there.

bathsheba_c

First of all, your body adjusts your metabolism when you restrict calories. Yo-yo dieters in particular have the problem that they've slowed their metabolism way down.

Secondly, you have to factor in inaccuracies in measuring how much food you've eaten and how many calories you've burned. People think that a teaspoon or a cup are way bigger than they are.

Third, everything here is an average, and people can fall on various sides of the bell curve. Heck, even the calorie counts of foods are an average.

mulderpf

And that's exactly why people who need to lose a lot of weight don't just stop eating altogether.

Our bodies can only process so many calories from a source at a time - if we were to stop eating altogether, we cannot expect our bodies to simply take it from fat, it's also the same thing as if you were to gorge yourself on 8000 calories for the day, you wouldn't instantly gain 2 pounds (permanently).

The 3500 calorie-rule works when things are done in moderation. Any extreme would exert too much stress in your body and the outcomes aren't very predictable. But sticking to some of the basics and limits (such as eating at least 1200 calories), we know that the "rule" is fairly accurate over the long term.

Weight-loss and weight-gain are both medium to long-term things. It's based on averages rather than specifics. If you overeat by 1750 calories one day, doesn't mean you will be 0.5 pounds heavier the next and if you undereat by 1750 the next, doesn't mean you will be 0.5 pounds lighter the next. But, if you cut 3500 calories over 2 weeks, you are very likely to lose a pound (if you use trend weights rather than actuals).

It's a bit like investing - if someone tells you if you investing X amount in stock ABC, you'll gain 20% in five years, you need to see it through and wait until the end to see exact results. If you were to take daily snapshots, you'll probably run away because of daily fluctuations, but in the long-term, the stock might be going for a 20% growth. Maybe not 100% exact, but that's the analogy with weight too. It's usually close enough, unless something catastrophic happens - same thing with our bodies. If we do it with a fair amount of moderation, it will work, we just have to manage it properly.

The other side of the coin is also that many people tend to over- or under-estimate calorie intake and expenditure. I have seen it time and time again. People don't weigh things and expect the calories to be accurate (especially the calorie dense foods like fats and carbs!!). Inaccuracies in what would seem like accurate measurements can mean that people are off by as much as 300 calories a meal!!!

http://www.youtube.com/watch?v=JVjWPclrWVY

1sophiesophie

(Totally non-scientific response - more of an opinion about the approach):

I think the whole concept of calorie counting is to work off guidelines (nobody can really tell how much of the oil that you put in that frying pan was soaked up by the food, or how much of that particular 200g of sirloin steak was fat vs. lean meat. Similarly, I think we all get different results for the various exercises we do, in order to work out our net calories. It is all "best estimate" stuff and I think the same goes with the 3500 cal = lb thing. Scientists can work out how much energy is in a 1lb of fat, but just like the items above, we don't really know how the body will respond vs all the other variables at play. However, I still believe that unless you have some properly identified condition, then over a long enough period of time, the "less in, more out" equation, wins through.

1sophiesophie

The other side of the coin is also that many people tend to over- or under-estimate calorie intake and expenditure. I have seen it time and time again. People don't weigh things and expect the calories to be accurate (especially the calorie dense foods like fats and carbs!!). Inaccuracies in what would seem like accurate measurements can mean that people are off by as much as 300 calories a meal!!!

TOTALLY AGREE WITH THIS. Also like the investing analogy....

zyxst

What works in a lab doesn't always work IRL.

Findingmyathlete

I think what others have already mentioned is true. Not everyone calculates the calories accurately.
I also think that the type of food you put in your body can affect how fast you lose weight. You can still lose weight
eating under calorie eating junk. But you are likely to lose weight more efficiently if you're eating clean.

drmerc

:drinker:

Jimaudit

The other comical thing is to hear folks say "as long as you eat to your calories, it doesn't matter what you eat"....WHAT A LOAD OF CRAP.

So many folks on here eat fast food, stay within their cal goals and lose no weight. Wanna know why? Fat and sodium. May fit into your cal goals but the intake of trans fat and sodium will kill all your other efforts. Or they eat an apple for the next meal and think they have balanced their goals for the day.

Its ok to have a cheat day, but do not expect to eat that type of processed food on a regular basis and hit your goals.

sijomial

You have hit on the difference between rules and guidelines...
"Rules are for the observance of fools and the guidance of wise men."

My weekly calorie deficit was 3,500 but I didn't lose a pound a week. Adjusted my targets to a 4,500 deficit and I am now losing a pound a week. Doesn't really matter why 3,500 didn't achieve it in the end. I've always seemed to have to try harder than others but I've found what works for me.

gdrmuzak

1) Counting calories is generalization, there are still variations & inaccuracies.
2) Variations is water weight
3) Changing metabolisms
4) Varying diet/nutrition and balances of carbs, proteins, fiber, vitamins, deficiencies, etc
5) Weight training vs. all cardio
6) Stress
7) Lack of sleep (quantity and/or quality)


Personally, I've lost a total of 12 lbs with MFP in less than two months. Eight lbs. quickly then I plateaued for three weeks and I've dropped another four lbs. in the past few weeks.

Six years ago while going through a divorce, I only lost 3-4 lbs over 6-7 weeks even though I was exercising 6-7 days/week and not over eating. Then all of a sudden my body kicked into high gear and even though I wasn't working out daily, I lost 20 lbs in two months.

My point: there are a lot of variables that impact our weight fluctuations and someone else's differing results.

kuntry_navy

Day to day changes are more due to water than anything. Best bet is to eat at a certain caloric level or plan and then adjust from there.

just what i was gonna say. water weight

TheVimFuego

It's a very, very rough guideline, no more.

The assumption that 1lb of fat contains 3500 calories is very inaccurate for starters.

The assumption that the body *has* to liberate fat in the face of an energy deficit is wrong. The body has to do something but giving up fat isn't necessarily it.

The calorie counts for the various foods are broad estimates and the estimates of exercise calories are ludicrously out.

And all the rest (sleep, stress, metabolism, daily macros, etc as others have said).

It's deeply flawed but somehow it gets trotted out as fact everywhere because nobody can generally be arsed to question it.

annehart00

3500 Calories To Lose A Pound – Is This Formula All Wrong?
By Tom Venuto, NSCA-CPT, CSCS
www.burnthefat.com

Most fitness conscious people have heard that there are 3,500 calories in a pound of fat, so if you create a deficit of 3500 calories in a week, you lose a pound of weight. If you create a deficit of 7000 calories in a week, you lose two pounds, and so on. Right? Well, not so fast…

Dr. Kevin Hall, an investigator at the National Institute of Health in Bethesda has done some interesting research about the mechanisms regulating human body weight. He recently published a new paper in the International Journal of Obesity that throws a wrench in works of the “3500 calories to lose a pound” idea.

Some of the equations in his paper made my head hurt, but despite the complex math he used to come to his conclusions, his article clearly prompts the question, “3500 calories to lose a pound of WHAT?” His paper also contained a lot of simple and practical tips you can use to properly balance your caloric intake with output, fine tune your calorie deficit and help you retain more muscle when you diet.

Below, I’ve distilled some of the information into a simple bullet-point summary that any non-scientist can understand. Then I wrap up with my interpretation of how you can apply this data in your own fat loss program:

Calculating the calories required to lose a pound and fine-tuning your caloric deficit

■3500 calories to lose a pound has always been the rule of thumb. However, this 3500 calories figure goes back to research which assumed that all the weight lost would be adipose tissue (which would be ideal, of course).
■But as we all know (unfortunately), lean body mass is lost along with body fat, which would indicate that the 3500 calorie figure could be an oversimplification.
■The amount of lean body mass lost is based on initial body fat level and size of the calorie deficit
■Lean people tend to lose more lean body mass and retain more fat.
■Fat people tend to lose more body fat and retain more lean tissue (revealing why obese people can tolerate aggressive low calorie diets better than already lean people)
■Very aggressive low calorie diets tend to erode lean body mass to a greater degree than more conservative diets
■Whether the weight loss is lean or fat gives you the real answer of what is the required energy deficit per unit of weight loss
■The metabolizable energy in fat is different than the metabolizable energy in muscle tissue. A pound of muscle is not 3500 calories. A pound of muscle yields about 600 calories.
■If you lose lean body mass, then you lose more weight than if you lose fat.
■If you create a 3500 calorie deficit in one week and you lose 100% body fat, you will lose one pound.
■But if you create a 3500 calorie weekly deficit and as a result of that deficit, lose 100% muscle, you would lose almost 6 pounds of body weight! (of course, if you manage to lose 100% muscle, you will be forced to wear the Dieter’s Dunce cap)
■If you have a high initial body fat percentage, then you are going to lose more fat relative to lean, so you may need a larger deficit to lose the same amount of weight as compared to a lean person
■Creating a calorie deficit once at the beginning of a diet and maintaining that same caloric intake for the duration of the diet and after major weight loss fails to account for how your body decreases energy expenditure with reduced body weight
■Weight loss typically slows down over time for a prescribed constant diet (the “plateau”). This is either due to the decreased metabolism mentioned above, or a relaxing of the diet compliance, or both (most people just can’t hack aggressive calorie reductions for long)
■Progressive resistance training and or high protein diets can modify the proportion of weight lost from body fat versus lean tissue (which is why weight training and sufficient protein while on calorie restricted diets are absolute musts!)
So, based on this info, should you throw out the old calorie formulas?

Well, not necessarily. You can still use the standard calorie formulas to figure out how much you should eat, and you can use a 500-1000 calorie per day deficit (below maintenance) as a generic guideline to figure where to set your calories to lose one or two pounds per week respectively (at least that works “on paper” anyway).

Even better however, you could use this info to fine tune your caloric deficit using a percentage method and also base your deficit on your starting body fat level, to get a much more personalized and effective approach:

15-20% below maintenance calories = conservative deficit
20-25% below maintenance calories = moderate deficit
25-30% below maintenance calories = aggressive deficit
31-40% below maintenance calories = very aggressive deficit (risky)
50%+ below maintenance calories = semi starvation/starvation (potentially dangerous and unhealthy)

(Note: According to exercise physiologists Katch & Mcardle, the average female between the ages of 23 and 50 has a maintenance level of about 2000-2100 calories per day and the average male about 2700-2900 calories per day)

Usually, we would suggest starting with a conservative deficit of around 15-20% below maintenance. Based on this research, however, we see that there can be a big difference between lean and overweight people in how many calories they can or should cut.

If you have very high body fat to begin with, the typical rule of thumb on calorie deficits may underestimate the deficit required to lose a pound. It may also be too conservative, and you can probably use a more aggressive deficit safely without as much worry about muscle loss or metabolic slowdown.

If you are extremely lean, like a bodybuilder trying to get ready for competition, you would want to be very cautious about using aggressive calorie deficits. You’d be better off keeping the deficit conservative and starting your diet/cutting phase earlier to allow for a slow, but safe rate of fat loss, with maximum retention of muscle tissue.

The bottom line is that it’s not quite so simple as 3,500 calories being the deficit to lose a pound. Like lots of other things in nutrition that vary from person to person, the ideal amount of calories to cut “depends”…

Note: The Burn The Fat, Feed The Muscle program not only has an entire chapter dedicated to helping you calculate your exact calorie needs, it was designed very specifically to keep a fairly conservative approach to caloric deficits and to maximize the amount of lean tissue you retain and minimize the amount of metabolic adaptation that occurs when you’re dieting. The approach may be more conservative, and the fat loss may be slower, but it has a better long term track record… You can either lose weight fast, sacrifice muscle and gain the fat back like 95% of people do, or lose fat slow and keep it off forever like the 5% of the people who know the secrets. The choice is yours. For more information, visit: www.burnthefat.com

References:

Forbes GB. Body fat content influences the body composition response to nutrition and exercise. Ann NY Acad Sci. 904: 359-365. 2000

Hall, KD., What is the required energy deficit per unit of weight loss? Int J Obesity. 2007 Epub ahead of print.

McArdle WD. Exercise physiology: Energy, Nutrition, and Human performance. 4td ed. Williams & Wilkins. 1996.

Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 6: 542-546.

ablitchok

It also depends on how much you need to lose. The more overweight you are, the faster your body will respond to initial efforts to lose weight. As you get closer to a healthy number, you body adjusts and begins to work more efficiently, making it harder to shed the last 5-10 pounds. This is when you really have to work on shocking your body and the type and timing of your calories begins to make a difference. Getting rid of those final vanity pounds really becomes an exercise in patience and science. You might have to do some experimenting. The key is not to get discouraged and sabotage the work you have done.

AngelDog1

Very interesting read annehart. Thanks for posting!

T1mH

bump for future reference

mulderpf

■Weight loss typically slows down over time for a prescribed constant diet (the “plateau”). This is either due to the decreased metabolism mentioned above, or a relaxing of the diet compliance, or both (most people just can’t hack aggressive calorie reductions for long)

I was actually looking for inaccuracies or stupid claims in this (just because it irks me so much when people put letters behind their names to try and give themselves extra credibility), but I actually like this article and the content. I also think the quote above does answer for a lot of issues that people are experiencing, either that, or the size of their spoons and cups start increasing as they lose weight...hahaha.

annehart00

I don't agree with this nutritionist on some things but since this is just working out calculations - I think this one is interesting too...


1lb does not equal 3,500 calories
By Zoe Harcombe
http://www.zoeharcombe.com/the-knowledge/1lb-does-not-equal-3500-calories/

One of the most commonly held diet myths is “To lose one pound of fat you need to create a deficit of 3,500 calories”. This is wrong at every level. First of all, one pound does not equal 3,500 calories. You will see this formula in government literature, in just about every diet book, in private health booklets and all over the internet. The next time you see it, or hear it, ask where it comes from. You will not get an answer. (I asked the following seven UK organisations: the National Health Service (NHS); the National Institute for Clinical Excellence (NICE); the Department of Health; the National Obesity Forum; the Association for the Study of Obesity; the British Dietetic Association and Dieticians in Obesity Management and five of these have no idea where it even comes from. The two that tried to prove it failed by a factor of about ten.)

The first part of the calorie formula is the assertion that one pound of fat contains 3,500 calories. You will struggle to find anyone who can demonstrate the precise calculation behind this, so I’ll offer this as a suggestion:

1) One pound equals 454 grams (decimal places aside, this is a fact);

2) Fat has nine calories per gram (this is the universally accepted conversion, but it is an estimate and significantly rounded down from even the original estimate);

3) Human fat tissue is approximately 87% lipid (this is a widely accepted conversion, but it is also an estimate).

Putting these together, we can derive the sum that 454 grams of body fat tissue has approximately the calorific energy of 395 grams of pure fat (454 grams x 87%), that is 3,555 calories (395 grams x 9).

3,555 is close enough to 3,500 you may think, until you see the absurdity of how precisely the formula is applied. According to those who believe this formula, this difference of 55 calories (in this case from the calculation being approximate) would make five to six pounds difference a year. The National Obesity Forum web site states “one less (sic) 50 calorie plain biscuit per day could help you lose 5lbs (2.3kg) in a year – and one extra biscuit means you could gain that in a year!” (Ref 2) No it won’t. I can’t even get an estimate of the formula to closer than 55 calories ‘out’. Even if the 3,555 were correct (and it isn’t), this would mean we all need a 55 calorie biscuit, no fewer, every day or we will be five pounds lighter in a year anyway. Every person who didn’t have that biscuit every day should have lost 141 pounds over the past 25 years.

With little effort I can find evidence in obesity journals that fat has anywhere between 8.7 and 9.5 calories per gram. The same (1911) obesity journal that says that human fat tissue can be 87% lipid also says that it may be 72% lipid.

Taking the extremes of these, we can establish a range whereby one pound of fat could contain anywhere between 2,843 and 3,752 calories. Given that it is currently held that one pound is 3,500 calories we could (according to this formula) inadvertently gain six stone every year at the low end of the calculation and lose almost two stone in the same year if one pound is 3,752 calories. Don’t worry about any of this – because the formula doesn’t hold at any other level either.

Ref 2: http://nationalobesityforum.org.uk/families/before-you-start-mainmenu-110/34-how-weight-loss-works.html (See reference 78 The Obesity Epidemic).