Why not eat below BMR?

I'd love someone to answer the second part of OPs question about consuming vs. netting because it really confuses me. Is the conventional wisdom not to EAT less than BMR or not to NET less? I run a lot so a normal day burns 300- 600 calories. I never eat below my BMR, but often with exercise I will net below it. An outlier example is today- I ran 12 miles and burned at least 1000 cals....no way I can eat all that back!!

Help explain if its about netting or eating please!

Pathetically quoting myself because I'd love a clear explanation about the eating vs. netting issue....any thoughts?

After a long run it's good to eat carbs to replenish your muscle glycogen stores. If you are doing so much physical activity as to potentially net less than your BMR, and if this is something you do on a frequent basis, you probably need to up your intake with more nutritionally dense foods. The sort of performance you're talking about - - running 12 miles - - is extremely demanding and draining on your body, and it would be important for you to eat those calories back. Additionally, if you're performing at that level of fitness already, you don't want a large calorie deficit. You're probably looking to shed fat and perform body recomposition - that is best accomplished with a narrow deficit and time.

Stated more simply, shoot to net no less than your BMR at the absolute minimum, and as has been observed, calibrate on the basis of your TDEE.

With love,
Burt

Hm, so what you're saying seems to be slightly different than the poster above, but if I'm understanding correctly you both feel that netting SUBSTANTIALLY less than BMR is the issue, not so much netting a bit under?

Burt, I completely agree about long runs and carbs, and I certainly eat MORE on those days, but usually only by 400-500 cals, not the full 1000+, know what I mean? But I certainly agree about properly refueling...honestly I'm just full at that point (and sometimes a bit queasy for an hour or so after I finish a run.)

Thanks for the suggestions fellas!

The problem is running too large a calorie deficit. The calorie deficit is based on TDEE and your food intake. That's it. BMR only factors into it as a way to help you calculate your TDEE.

Once you know TDEE, BMR has no relevance whatsoever. You want a moderate calorie deficit . 250-500 if you don't have a lot of weight to lose and 500-750 if you have a lot of weight to lose.

I really find the argument silly and non existent. And just to be blunt, I'm not even friends with the above person so I have no horse in this race so to speak, but the bolded part is correct. I'd use a percentage but that's sort of an aside to the point.

If you have a low TDEE due to low NEAT or EAT, you may in fact have to eat below BMR and if you're using a system where you eat back exercise calories and consequently eat less on rest days, you're very very likely going to be eating under BMR on rest days. And there's no real problem with that.

Now that being said, there are plenty of people who create too big of an energy deficit (which could be bad) but it looks like the poster above has already addressed that.

Create your deficit off of TDEE and make sure it's reasonable (20% is a reasonable starting point for most people)and whether or not it's below BMR on some days really does not matter if you did the underlined part correctly.

So if my TDEE is 2075 and my BMR is 1725, I should run a deficit of no more than 350 calories?

Johnnythan, I think their argument would be that anyone in this situation needs to exercise more to make the mathematical obstacle disappear.

I had a trainer explain it like this to me "If you were in a coma, the hospital would feed you your BMR via IV just to keep you alive." Why would you feed yourself less than coma state?

Kindof made sense to me

I had a trainer explain it like this to me "If you were in a coma, the hospital would feed you your BMR via IV just to keep you alive." Why would you feed yourself less than coma state?

Kindof made sense to me

Because you're not trying to maintain your weight like they are in the hospital. You're intentionally losing weight.

Good point to consider ...... also, LOVE your hat! Rarrwwwrrr!

I do not think it is about organs but more about muscle?

But having said that not feeding your body as a whole organism will eventually deplete and drain ie skin, hair, nails will not do well if you do not feed your body in a good way.

You will find lots of scientific evidence that anorexics can deplete their organs by eating below the BMR consistently.

This is the short answer, you sound educated, so you would not need me to tell you any of this?

Ever heard of Google Scholar? A simple search for "Basal Metabolic Rate" will answer a lot of your questions. For example:

http://ajpendo.physiology.org/content/293/6/E1580.full

This describes a study comparing water only, VLED (very low energy diet, 600 kcal/day 2.5 MJ), and maintenance diets. They did not find differences in protein breakdown between the full starvation and the VLED group--both showed signs of protein breakdown, though with different effects on blood sugar and so on.

At a nominal 5% weight loss, whole body protein oxidation and the synthetic rates of specific hepatic export proteins were increased in the starvation group (rapid weight loss) compared with subjects receiving VLED (slower rate of weight loss), where most of these parameters were either unchanged or reduced. The increase in whole body protein oxidation during starvation supports previous studies with lean individuals (40, 53, 69, 70). This contrasts with the VLED treatment, where protein synthesis, breakdown, and oxidation were reduced during weight loss (significant at 7% weight loss relative to the baseline values for synthesis and breakdown only). This agrees with earlier observations that long-term nutrient restriction, either with low-protein or protein-free diets, leads to an adaptation with reduced protein turnover and lowered amino acid catabolism (9, 11).

Such understanding may lead to improved management strategies of these or similar situations. However, we should not extrapolate our findings to overweight or obese individuals undergoing weight loss who may respond differently to starvation and VLED than our initially lean subjects. In addition, we do not know how these mechanisms may be modified by coexistent disease or injury, and these remain areas for further investigation.

Here is a novel concept:
Pick a number - or let MFP do it for you, or Scooby or IPOARM or ........
Net that many calories for a month.
Did your body change in the ways you want/expect it to?
If yes, continue.
If not, adjust calorie intake accordingly and reassess in another month.

And the plan is TDEE - 20% or some other reasonable deficit. TDEE - 20% can be below BMR on days you don't work out. Derp.