Averages or set values?

magic8

magic8

New member
In many threads on this forum, people talk about RMR, BMR, heart rate, metabolism, calorie expediture, etc. in terms of averages. As I understand it, the values you get from the calculator programs are based on average values across many people. I was wondering if anyone knows which values are based on a population mean, and which are absolute? For example, is it absolutely true that 3,500 calories = one pound, or is that a mean estimate?

I ask because some people seem to be able to eat a lot of calories and don't exercise, but still maintain a low weight. Conversely, I have a cousin who works out daily and eats only about 800 cals a day (she has disordered eating) and has maintained a normal weight for years. Is that because the 3,500 cal per pound thing doesn't apply equally to all, or because those individuals' metabolisms are just working differently? Is it that the BMR calculations don't apply equally to all? In any case, some of the calculations are off somewhere. I know it's not exact, but I'm not sure where the discrepancy lies.
 
There are 3500 calories in a pound of body weight lost on average. You better believe that this is not an exact number.

The numbers are as follows.

A pound of fat in you is 4200 calories worth of crap.
A pound of carbs will range from 1750-1900 calories (1860 is the mean number).
A pound of protein is likewise considered 1860 but I personally believe it is closer to 1950-2000.

On average it is estimated that you need a 3500 calorie deficit to lose a pound of body weight, but obviously that fluctuates depending on your body composition.

Your friend who says she is eating 800 calories a day and maintains a normal weight is lying. Sorry! It has been shown time and time again in scientific studies that people massively under-report those types of calorie deficits. Any examples (like the Minnesota study from a long time ago) that involve exact calorie monitoring show massive amounts of weight loss once you hit 1500 calories, let alone 800 calories.

Metabolic rates do differ between people based on numerous criteria: age/bone density/height/weight/hydration being the most pertinent. However the fluctuation, once you account for these variables, is less than 20% between individuals.

Michael
 
Everything you say makes sense, and the whole calorie per pound formula thing is more understandable as an average value.

Don't we all know people who seem to eat way more than "normal" but who aren't overweight? I was trying to figure out which part of the formula wasn't exact--and it seems it's all of it.

As far as my cousin goes, she has anorexia-type behavior but doesn't meet diagnostic criteria because she's not 15% under her ideal body weight. She is probably at the low end of normal, but doesn't have any visible fat on her whatsoever. She has a low normal BMI but looks skeletal. Since anorexics often binge after long periods of restricting, it could be that she's not counting binges into her daily calories. However, I lived with her for a month and only saw her eat fruit and black coffee, ever. She may have been eating in secret, but she surely wasn't eating very much.

So what do you think about sub-clinical anorexics? I think it's called ED-NOS, or eating disorder, not otherwise specified. I have chatted with these folks before, and many claim that they stop losing weight at 1000 calories a day. Do you think this is possible? Of course, they are sick, feel like crap, lose their hair, stop menstruating, and can't make it up a flight of stairs, but some actually complain that they can't get down to diagnosable anorexia. Is this because they are bingeing in secret, or because the body can adapt to live on minimal calories? The Minnesota study you talk about used healthy men as their participants, and the restricted diet messed them up for life (many continued to hoard food the rest of their lives). They lost a lot of weight, but the study was designed to examine the psychological effects of semi-starvation. The anorexics I'm talking about are mostly young, small girls. Although not healthy, many claim to be maintaining a low but normal weight despite very strict diets.

Are they lying, or are individual differences this extreme? Just wondering. And does anybody know whether the body will return to normal after starvation, and how long it takes? On average, of course!
 
The RMR for a young girl 20 at 5'4 weighing 105 lbs is 1250. This can be adjusted by starvation by up to 30%. This could result in a RMR of 875 calories + activity...which for someone who is bordering on anorexia could be as low as 150-200 calories a day.

That's in the range of 1000-1100 calories a day for maintenance.

Starvation over a long period of time is the only thing that screws up the metabolic equations. That is also why anorexics do plateau (eventually) around 1000 calories.

After severe calorie reduction, it takes about 3-4 weeks to regain 80% of that metabolic function, and 2-3 months for it to become normal again. It is not permanent.

Edit: Fruit has lots of sugar in it and can sustain someone with carbs. And people with eating problems HATE eating in front of others. So very likely there was a binge eat or two here or there. Only takes one good hidden binge a week to keep a visible daily intake of 600-700 calories a day in the 1000-1100 range overall for the week.
Michael
 
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Thanks for the great response, Michael. Makes total sense.

So, just for the sake of conversation, what do you think about people who are low/normal weight, but seem to eat tons? Again, with the anecdotal evidence: I know a tiny, skinny girl who loves to eat, eats tons, and seems to be able to eat whatever she wants without gaining weight. She just does not gain weight no matter what she eats (she says). She is not bulimic, and has a healthy attitude toward food and her body. She has used the tools available on this forum to calculate her daily intake, output, and BMR. From the calculations, she should be gaining weight because she takes in more than she expends, but she's not. She has had trouble keeping weight on for most of her life. It is only now in her 30s that she is able to maintain a low but normal weight.

So, which of the following options do you think is most likely?
1) she only eats when she's around me and lies about eating the same way at home, and is overestimating the calories she consumes
2) she is getting more exercise than she thinks she's getting
3) she's secretly puking up her huge meals (I seriously doubt this, knowing her)
4) her metabolism is significantly faster than an average woman of her height
5) it takes her body more than 3,500 calories to gain one pound

This is just for my curiosity, wondering why (and how much) people vary with regard to these formulas. Thanks for indulging me!
 
1) + 2) + 4) + 5)

Jitterbugs burn many more calories over time just by being all over the place. If someone is on the go and always moving that can account for a lot.

She might not stuff her face as much as she think she does. Perhaps she eats larger meals less frequently and/or avoids the real high calorie foods. Like the guy who is considered a pig because he eats 3 double cheeseburgers instead of someone who eats one cheeseburger + fries with ketchup/mayo + a coke. You arrive at around the same calorie amount.

Her metabolism may be 10% faster than other peoples.

It might take more than 3500 calories of surplus to gain a pound of weight. Without exercise generally it will be primarily fat and could definitely be in around 4000 calories.

All these factors together play a role. Just remember that the anecdotal evidence or the common sense thought of "look at that family, they're naturally skinny while that family is filled with a bunch of obese people, it must be genetic" doesn't take into account the environmental modifiers within that group.

Michael
 
My girlfriend does not exercise after work at all because she is on her feet all day at work. She mostly does setup of retail displays for a major retailer. She hates the idea of exercise (probably because it reminds her of work).

Does your friend who 'eats a bunch' have a very active job (on her feet) or simply insist on being 'busy all the time' outside of work? She may not be working out, but instead be quite active in other ways...?
 
NEAT is our friend. :)

***********************

J Appl Physiol. 2006 Jan;100(1):249-57. Epub 2005 Sep 29. Links
Physical inactivity amplifies the sensitivity of skeletal muscle to the lipid-induced downregulation of lipoprotein lipase activity.
Zderic TW, Hamilton MT.

E102 VMB, 1600 E. Rollins Rd., Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, Missouri 65211, USA. hamiltonm@missouri.edu

Physical inactivity is a risk factor for lipoprotein disorders and the metabolic syndrome. Physical inactivity has a powerful effect on suppressing lipoprotein lipase (LPL) activity in skeletal muscle, the rate-limiting enzyme for hydrolysis of triglyceride (TG)-rich lipoproteins. We tested the ability of several compounds to prevent the decrease in LPL. The present study minimized standing and ordinary light nonexercise movements in rats to compare the effects of inactivity and nonexercise activity thermogenesis (NEAT) on LPL activity. The key new insight was that the typically quick decrease in LPL activity of oxidative muscle caused by physical inactivity was prevented by nicotinic acid (NA), whereas inhibitors of TNF-alpha, inducible nitric oxide synthase, and NF-kappaB had no such effect. NA was administered at a dose known to acutely impede the appearance of plasma TG from the liver and free fatty acids from adipose tissue, and it was effective at intentionally lowering plasma lipid concentrations to the same level in active and inactive groups. As measured from heparin-releasable LPL activity, LPL in the microvasculature of the most oxidative muscles was approximately 90% lower in the inactive group compared with controls, and this suppression was completely blocked by NA. In contrast to inactivity, NA did not raise muscle LPL in ambulatory controls, whereas a large exogenous fat delivery did decrease LPL activity. In vitro control studies revealed that NA did not have a direct effect on skeletal muscle LPL activity. In conclusion, physical inactivity amplifies the ability of plasma lipids to suppress muscle LPL activity. The light ambulatory contractions responsible for NEAT are sufficient for mitigating these deleterious effects.
 
People who are naturally inclined to move more are less likely to get fat.

That's not exactly what that study was about above, but it's the point I was trying to make.
 
Here's another:

**************************

--------------------------------------------------------------------------------

Clin Nutr. 2007 May 19; [Epub ahead of print] Links
BMR variability in women of different weight.

* Marra M,
* Pasanisi F,
* Montagnese C,
* De Filippo E,
* De Caprio C,
* de Magistris L,
* Contaldo F.

Interuniversity Center for Obesity and Eating Disorders, Department of Clinical and Experimental Medicine, Federico II University, 80131 Naples, Italy.

BACKGROUND & AIM: Non-exercise activity thermogenesis (NEAT) and substrate oxidation are significant components of Energy Balance; their regulation may be modulated according to nutritional status and their impairment has been advocated as a factor facilitating the development of excess body fat. METHODS: In this study body composition, resting metabolic rate (RMR), fidgeting as a component of NEAT and respiratory quotient (RQ), an index of preferential substrate oxidation, have been evaluated in 80 young women: 20 restrictive anorexia nervosa (rAN: BMI 15.1+/-1.6kg/m(2)); 20 constitutional leanness (CL: BMI 17.2+/-1.0); 20 obese patients (Ob: BMI 43.8+/-10.0) and 20 controls (CTR: BMI 21.7+/-2.4). RESULTS: Fat free mass, fat mass and RMR progressively increased from rAN to Ob (p<0.05). Fidgeting was higher in CL (67.2+/-27.2kcal; p<0.05) than in the other groups. Lipid oxidation, evaluated with RQ showed a negative correlation with fidgeting in CL (r=-0.433; p<0.05) and positive in Ob (r=0.572; p<0.05) and in rAN (r=0.434; p<0.05). CONCLUSION: Our findings support the regulatory function of NEAT, its protective role to prevent excess body fat accumulation and its positive relation with fat oxidation in CL.
 
Steve is a great resource. Excellent info.

Michael
 
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