Re: exercise and food restriction

[Guest guest]

Below is a reference that does not answer the question of whether

exercise and CR are compatible for longevity, but it concludes that

exercising while fasting burns more fat.

Tony

>>>

From: " Rodney " <perspect1111@y...>

Date: Tue Nov 9, 2004 3:16 pm

Subject: Re: exercise and food restriction

>>>

Enevoldsen LH, Simonsen L, Macdonald IA, Bulow J, " The combined

effects of exercise and food intake on adipose tissue and splanchnic

metabolism " , J Physiol. 2004 Oct 21,

Food intake before exercise reduced whole body lipid combustion during

exercise to about 50% of the combustion rate found during exercise in

the fasted state.

It is concluded that exercise performed in the fasted state shortly

before a meal leads to a more favorable lipid metabolism during and

after exercise than exercise performed shortly after a meal.

PMID: 15498802

[Guest guest]

Hi Tony:

That is interesting. It seems to me that, superficially, it is in

conflict with the proposition from an earlier post, which suggested

that rapid weight loss (a greater state of 'fasting' than slower

weight loss) is supposed to be associated with greater loss of **lean

body mass**.

Not sure what to make of this.

Rodney.

>

> Below is a reference that does not answer the question of whether

> exercise and CR are compatible for longevity, but it concludes that

> exercising while fasting burns more fat.

>

> Tony

>

> >>>

> From: " Rodney " <perspect1111@y...>

> Date: Tue Nov 9, 2004 3:16 pm

> Subject: Re: exercise and food restriction

> >>>

>

> Enevoldsen LH, Simonsen L, Macdonald IA, Bulow J, " The combined

> effects of exercise and food intake on adipose tissue and splanchnic

> metabolism " , J Physiol. 2004 Oct 21,

> Food intake before exercise reduced whole body lipid combustion

during

> exercise to about 50% of the combustion rate found during exercise

in

> the fasted state.

> It is concluded that exercise performed in the fasted state shortly

> before a meal leads to a more favorable lipid metabolism during and

> after exercise than exercise performed shortly after a meal.

> PMID: 15498802

[Guest guest]

>>>

From: " Rodney " <perspect1111@y...>

Date: Tue Nov 9, 2004 8:38 pm

Subject: Re: exercise and food restriction

That is interesting. It seems to me that, superficially, it is in

conflict with the proposition from an earlier post, which suggested

that rapid weight loss (a greater state of 'fasting' than slower

weight loss) is supposed to be associated with greater loss of **lean

body mass**.

Not sure what to make of this.

>>>

My interpretation is that the paper does not address rapid weight

loss, but rather establishes that exercise helps to mobilize lipids,

and if you are fasting, the lipids come from your fat stores, but if

you have eaten, the calories that you ingested are used in preference

to stored fat. I suppose that the reason for this is that after you

eat there are more carbs available to be used as fuel, and fat cannot

get (or does not need to be) mobilized.

This mechanism would make it possible to build muscle while reducing

fat by exercising before breakfast followed by a high protein, low

carb breakfast, which is what bodybuilders do in their final

preparation for competition. This is also confirmed by the following

paper which finds that lean mass is preserved if the caloric

restriction is not too severe and the diet has >50% protein.

>>>

J Nutr. 2004 Oct;134(10):2646-52.

Increasing the protein content in a carbohydrate-free diet enhances

fat loss during 35% but not 75% energy restriction in rats.

Marsset-Baglieri A, Fromentin G, Tome D, Bensaid A, Makkarios L, Even

PC.

A protein content > 50% preserved lean body mass at the expense of fat

mass when energy restriction was 35%. Our results show that the

absence of carbohydrates from the diet induces a low energy intake and

the preferential deposition of protein.

PMID: 15465761

>>>

Tony

>>>

> Enevoldsen LH, Simonsen L, Macdonald IA, Bulow J, " The combined

> effects of exercise and food intake on adipose tissue and splanchnic

> metabolism " , J Physiol. 2004 Oct 21,

> Food intake before exercise reduced whole body lipid combustion

during

> exercise to about 50% of the combustion rate found during exercise

in

> the fasted state.

> It is concluded that exercise performed in the fasted state shortly

> before a meal leads to a more favorable lipid metabolism during and

> after exercise than exercise performed shortly after a meal.

> PMID: 15498802

[Guest guest]

Hi Tony:

I don't have an opinion on this. But I know I am confused.

Let me put it another way. As I see it (I may be mistaken, of

course) in all cases - slow weight loss; rapid weight loss; and very

rapid weight loss (fasting) we are talking about a caloric deficit

which, in order to maintain normal functioning requires the body to

source the deficit from somewhere.

But the earlier study, which I had noted, said rapid weight loss (a

greater caloric deficit) uses more lean body mass for its source of

calories, than slow weight loss.

But the study you referenced says that fasting, i.e. very rapid

weight loss, uses mostly fat to make up the deficit. So do we really

have a 'U' shaped fat function here? Such that a small caloric

deficit and a very large caloric deficit burn fat, but a moderate

caloric deficit tends to burn mostly LBM?

Or is it saying that **exercise** is the factor that causes the fat

to be burnt during caloric deficit in preference to LBM, so that

the 'fasting' aspect is a bit of a red herring?

Do you see why I feel confused? Perhaps it is true that there is

a 'U' shaped function. Perhaps it is the exercise. Perhaps it is

something else. But I sure would need to see more evidence of that

before being convinced.

Rodney.

>

> >>>

> From: " Rodney " <perspect1111@y...>

> Date: Tue Nov 9, 2004 8:38 pm

> Subject: Re: exercise and food restriction

> That is interesting. It seems to me that, superficially, it is in

> conflict with the proposition from an earlier post, which suggested

> that rapid weight loss (a greater state of 'fasting' than slower

> weight loss) is supposed to be associated with greater loss of

**lean

> body mass**.

> Not sure what to make of this.

> >>>

>

> My interpretation is that the paper does not address rapid weight

> loss, but rather establishes that exercise helps to mobilize lipids,

> and if you are fasting, the lipids come from your fat stores, but if

> you have eaten, the calories that you ingested are used in

preference

> to stored fat. I suppose that the reason for this is that after you

> eat there are more carbs available to be used as fuel, and fat

cannot

> get (or does not need to be) mobilized.

>

> This mechanism would make it possible to build muscle while reducing

> fat by exercising before breakfast followed by a high protein, low

> carb breakfast, which is what bodybuilders do in their final

> preparation for competition. This is also confirmed by the

following

> paper which finds that lean mass is preserved if the caloric

> restriction is not too severe and the diet has >50% protein.

>

> >>>

> J Nutr. 2004 Oct;134(10):2646-52.

> Increasing the protein content in a carbohydrate-free diet enhances

> fat loss during 35% but not 75% energy restriction in rats.

> Marsset-Baglieri A, Fromentin G, Tome D, Bensaid A, Makkarios L,

Even

> PC.

> A protein content > 50% preserved lean body mass at the expense of

fat

> mass when energy restriction was 35%. Our results show that the

> absence of carbohydrates from the diet induces a low energy intake

and

> the preferential deposition of protein.

> PMID: 15465761

> >>>

>

> Tony

>

> >>>

> > Enevoldsen LH, Simonsen L, Macdonald IA, Bulow J, " The combined

> > effects of exercise and food intake on adipose tissue and

splanchnic

> > metabolism " , J Physiol. 2004 Oct 21,

> > Food intake before exercise reduced whole body lipid combustion

> during

> > exercise to about 50% of the combustion rate found during exercise

> in

> > the fasted state.

> > It is concluded that exercise performed in the fasted state

shortly

> > before a meal leads to a more favorable lipid metabolism during

and

> > after exercise than exercise performed shortly after a meal.

> > PMID: 15498802