# To what extent can protein supplementation replace dietary protein?
**URL:** https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823
**Category:** Factual Questions
**Created:** [April 16, 2013, 9:08am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823 "2013-04-16T09:08:21Z")
**Posts on this page:** 12
**Page:** 2
### Author:  [@Richard\_Parker](https://boards.straightdope.com/u/Richard_Parker)
#### Post date: [April 24, 2013, 8:25pm UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/21 "2013-04-24T20:25:07Z")
Precisely.
---
### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [April 25, 2013, 2:06am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/22 "2013-04-25T02:06:26Z")
> [@astro](#):
>
> One lb of fat contains approx. 3600 food calories. The typical calorie range used in estimating the caloric deficit needed for a lb of fat loss is based on this estimate of calories per lb of fat, however within this context there is some debate over whether human body fat burn rate \*in the body \*can really be accurately gauged by this metric and if 3,600 calories of deficit will _really_ equal 3,600 of body fat loss. Based on my calorie counting over time I’ve found that it’s not an exact 1 to 1 correspondence of caloric deficit to fat lost, but it’s not all that far off and it suffices for general loss estimate projections when dieting.
>
> I’m not sure how you are projecting a real world deficit of 3000 cals per day. Baring some metabolic disease you would have to be working out like a professional athlete and eating at starvation levels to achieve that.
What I meant was that for every pound of fat, it can release about 30-40 (something like that) calories a day. So if you have 50 pounds of fat your deficit can’t be higher than 2000 calories a day. If you have 100 pounds of fat you can have a 4000 calorie deficit. So a pound of fat producing the maximum amount of fat would be totally spent by about 90 days.
When the super obese go on a diet some lose a hundred plus pounds within the first month. Some of that is water weight though, but the point is that the concept of ‘2 pounds a week’ is not the only way to determine caloric deficits. You can also determine it based on how many pounds of fat you have on your frame.
---
### Author:  [@astro](https://boards.straightdope.com/u/astro)
#### Post date: [April 25, 2013, 2:09am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/23 "2013-04-25T02:09:03Z")
SenorBeef, I read the thread where you described your super rapid weight loss. I think you are going to have accept the fact that those days are over. One of the body’s reactions to that sort of extreme loss rate is to re-calibrate your metabolism. Assuming that has happened short of medical intervention it’s not going happen again unless you do some sort of extreme fasting, the health impact of which would probably be fairly negative.
If you have gone through several significant gain loss cycles in your life, your body at this point your body has probably slowed down your everyday metabolism to the point is going to be fairly resistant to dropping weight quickly no matter what you do.
I understand you are impatient to carve the fat off, but a long term diet-exercise lifestyle plan will yield far greater benefits than a quick fix. I’ve dieted numerous times and lost big chunks of weight. Some time ago I gained a lot of weight to the point my life was fairly miserable. My boss suggested a personal trainer, but I was resistant because I know how to exercise and lose weight, so why did I need his help? I finally got onboard with a trainer and it’s made a world of difference.
I know you want to blow the weight off quickly, but I think you need to take a longer, slower view if you want to be successful. You’re just going to spin out if you insist on making this a sprint.
---
### Author:  [@Richard\_Parker](https://boards.straightdope.com/u/Richard_Parker)
#### Post date: [April 25, 2013, 2:14am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/24 "2013-04-25T02:14:03Z")
> [@astro](#):
>
> If you have gone through several significant gain loss cycles in your life, your body at this point your body has probably slowed down your everyday metabolism to the point is going to be fairly resistant to dropping weight quickly no matter what you do.
This is one hypothesis out there about how metabolism can adjust. AFAICT, most of the studies of this hypothesis have found no difference between subjects with prior significant gain/loss cycles and the control subjects, though I haven’t seen a meta-study.
---
### Author:  [@astro](https://boards.straightdope.com/u/astro)
#### Post date: [April 25, 2013, 2:40am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/25 "2013-04-25T02:40:41Z")
> [@Wesley\_Clark](#):
>
> What I meant was that for every pound of fat, it can release about 30-40 (something like that) calories a day. So if you have 50 pounds of fat your deficit can’t be higher than 2000 calories a day. If you have 100 pounds of fat you can have a 4000 calorie deficit. So a pound of fat producing the maximum amount of fat would be totally spent by about 90 days.
>
> When the super obese go on a diet some lose a hundred plus pounds within the first month. Some of that is water weight though, but the point is that the concept of ‘2 pounds a week’ is not the only way to determine caloric deficits. You can also determine it based on how many pounds of fat you have on your frame.
I’m not quite grasping your point. Assuming we’re not talking about the hyper obese, but obese people that want to lose say 50-150 lbs.
Let’s say I weighed 350 lbs and wanted to get to 250 lbs. So per your example I have 100 lbs of excess fat. My body requires approx. 10 calories per lb of body weight to maintain that level, so I am normally eating at least 3500 + calories per day on average. The difference between what I eat dieting-wise and this calorie support point based on my weight will generate an average calorie deficit that will tend to correlate with weight loss levels based on the assumption that a lb of fat has 3,600 cals and you need to generate that deficit via dieting to lose the lb of fat.
I have kept long term calorie counting records, and while this relationship metric can vary by individuals, and metabolism, and exercise levels the relationship of calorie deficit to weight loss over extended periods of time is pretty linear.
So let’s say hypothetically I’m 350 lbs and I have 100 lbs of excess fat how is this 40 cals per lb of fat - 4000 calorie daily deficit going to happen?
If you are saying that the _most_ of itself an individual lb of fat can “release” in a day is 40 cals I’m not familiar with that claim, but let’s say it’s correct for the sake of argument. Unless you are literally working out like an Olympic athlete which is unlikely in the extreme if you weigh 350 lbs how is this 4000 cals a day deficit occurring?
---
### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [April 25, 2013, 2:49am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/26 "2013-04-25T02:49:27Z")
My point is the rule of thumb is generally ‘lose 2 pounds a week’. But a different rule of thumb is keep your caloric deficit \*below \*what you get when you do the calculation
(pounds of fat on your body)\*(40)=max caloric deficit per day
A person with 100 pounds of fat shouldn’t run more than a 4000 calorie a day deficit. But if they did run up to 4000 calories a day, there is a decent chance most of it would be fat. If a person who only had 30 pounds of fat tried to run a 4000 calorie a day deficit, theoretically only 1200 of it can physiologically be fat (30\*40=1200) the other 2800 have to come from lean tissue. A person who only has 30 pounds of fat can’t physiologically mobilize 4000 calories of fat a day.
It is supposed to be a means of determining an upper limit on caloric deficits and is based on the assumption that the deficit up to that max number will be mostly fat, but after that max number it will be mostly lean tissue. A person with 50 pounds of fat who runs a deficit up to 2000 calories a day will lose mostly fat. A person who goes over that 2000 calories a day deficit will start losing lean tissue instead of fat.
I don’t know the exact number, but I have heard of this theory from several sources. If I can find a cite I will post it.
---
### Author:  [@astro](https://boards.straightdope.com/u/astro)
#### Post date: [April 25, 2013, 2:58am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/27 "2013-04-25T02:58:21Z")
> [@Richard\_Parker](#):
>
> This is one hypothesis out there about how metabolism can adjust. AFAICT, most of the studies of this hypothesis have found no difference between subjects with prior significant gain/loss cycles and the control subjects, though I haven’t seen a meta-study.
In looking you are correct that apparently the metabolism can come back, however it’s my understanding that if you are primarily sedentary and carrying a big load of fat your _current_ metabolism is likely to fairly slow / highly efficient partly in response to the metabolic effects of that high fat ratio.
---
### Author:  [@DSeid](https://boards.straightdope.com/u/DSeid)
#### Post date: [April 25, 2013, 11:31am UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/28 "2013-04-25T11:31:35Z")
> [@Wesley\_Clark](#):
>
> … I don’t know the exact number, but I have heard of this theory from several sources. If I can find a cite I will post it.
It can be found on several bodybuilding sites (maybe a reasonable example of broscience?) and seems to stem from [this one article written by someone in a department of physics and astronomy.](http://www.ncbi.nlm.nih.gov/pubmed/15615615).
> [@](#):
>
> A limit on the maximum energy transfer rate from the human fat store in hypophagia is deduced from experimental data of underfed subjects maintaining moderate activity levels and is found to have a value of (290+/-25) kJ/kgd. A dietary restriction which exceeds the limited capability of the fat store to compensate for the energy deficiency results in an immediate decrease in the fat free mass (FFM). In cases of a less severe dietary deficiency, the FFM will not be depleted …
Which would convert into about 31 Cal/pound of fat.
I don’t have access to the actual article but somehow doubt that the experimental data referenced was verified across a wide range of fat percentage levels. From what I can gather the experimental data was the [1950 Minnesota Starvation Study](http://en.wikipedia.org/wiki/Minnesota_Starvation_Experiment) which began the starvation phase with all subjects at a normal weight. Extrapolating to all fat levels and all fat locations seems unwarranted.
The medical literature has ignored that one article and has _not_ found that individuals with large amounts of fat stores can drop fat and exclusively fat with severe calorie restriction according to any such formula.
---
### Author:  [@Random\_Design](https://boards.straightdope.com/u/Random_Design)
#### Post date: [April 26, 2013, 12:55pm UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/29 "2013-04-26T12:55:55Z")
> [@Poysyn](#):
>
> One more thing - if you cut your calories too much you will stop losing any fat at all - you need to consume enough to spur your metabolism.
That doesn’t quite make sense to me. This would mean that anyone with a few extra pounds could never become bone-thin (I’m thinking back to pics of concentration camp survivors I’ve seen).
Is there supporting evidence that eating too little will halt the body using stored fat for energy? Why would the body store energy it won’t ever use?
---
### Author:  [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)
#### Post date: [April 26, 2013, 1:23pm UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/30 "2013-04-26T13:23:39Z")
So does that mean that a person can run a calorie deficit of 30-40 cal/lb body fat before their metabilism slows down?
---
### Author:  [@DSeid](https://boards.straightdope.com/u/DSeid)
#### Post date: [April 26, 2013, 2:11pm UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/31 "2013-04-26T14:11:45Z")
> [@Random\_Design](#):
>
> That doesn’t quite make sense to me. This would mean that anyone with a few extra pounds could never become bone-thin (I’m thinking back to pics of concentration camp survivors I’ve seen).
> Is there supporting evidence that eating too little will halt the body using stored fat for energy? Why would the body store energy it won’t ever use?
No there is not. The statement made is false. The body will lose less fat and more fat free mass (FFM) and will slow down both metabolism and activity with severe restriction, but fat loss will still occur.
> [@Saint\_Cad](#):
>
> So does that mean that a person can run a calorie deficit of 30-40 cal/lb body fat before their metabilism slows down?
No. The point of my post was to be critical of that bodybuilder site claim, and to try to track down where it originated. The body actually adapts (in a variety of ways) with lesser degrees of calorie deficits and with weight loss below whatever it has as its “set point.”
---
### Author:  [@DSeid](https://boards.straightdope.com/u/DSeid)
#### Post date: [April 26, 2013, 3:22pm UTC](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823/32 "2013-04-26T15:22:07Z")
If you are into math [here](http://ajpendo.physiology.org/content/298/3/E449.long#app-1) is a more sophisticated modeling. I readily admit I cannot follow it completely, but perhaps you can. The upshot though (according to this model) seems to be that the rate of fat utilization as fat mass increases is subject to a 2/3s power rule, not a linear increase, reflecting “the hypothesis that basal lipolysis scales with adipocyte surface area.” Thus, theoretically, someone with say 100 pounds of fat, instead of a more typical 30 to 35 pounds, would be theoretically able run a calorie deficit (if metabolism and activity did not compensate to prevent such) sufficient to lose 4 to 5 pounds of fat a week rather than the 2 to 3 that that 30 to 35 pounds of fat more typical person could. (3 times more to the 2/3 power is roughly 2.) Such asumes enough protein to maintain FFM, micronutrients, etc. and enough resistance exercise to convince the body to maintain the muscle mass. That seems reasonable to me and the article _seems_ to validate the model, but I am not qualified to comment more than that.
[Previous page](https://boards.straightdope.com/t/to-what-extent-can-protein-supplementation-replace-dietary-protein/655823.md?page=1)