Why is it hard to lose excess fat?

[skyisblue]

Is it because we have to use energy to hydrolyze fat to glycerol and fatty acids and then use energy to convert them to intermediates in cellular respiration??

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[polf]

(i think) because the body utilizes glucose in bloodstream first, then goes to stored glycogen second, and then finally fat for energy. you have to deplete all glucose and glycogen energy source in your body before you start burning fat (usually 20 min into a moderately paced workout)

 

[StudentDentist]

I believe the scientific reason is...because of Xbox 360, TV, excessive drinking during fraternity parties, sitting in the library studying, carbs, beer, pizza, beer, beer, and slowed gluconeogenesis.

 

[Lonely Sol]

(i think) because the body utilizes glucose in bloodstream first, then goes to stored glycogen second, and then finally fat for energy. you have to deplete all glucose and glycogen energy source in your body before you start burning fat (usually 20 min into a moderately paced workout)

Yea, polf is right!!

Also, know the fatty acid chains are ussually really long and they are broken down into 2-C chains, then the coA is attached to the 2-C chain, which becomes acetyl-coA and then they enter the regular pathway.

Since, the chains are soo long, it will take a long time to be used up, rather than glucose, which incorporated itself directly. So, one fatty acid chain provides more energy, therefore takes longer time to be used up.

*Please correct me if I am wrong, this makes sense to me!!

 

[DailyDrivenTJ]

Yea, polf is right!!

Also, know the fatty acid chains are ussually really long and they are broken down into 2-C chains, then the coA is attached to the 2-C chain, which becomes acetyl-coA and then they enter the regular pathway.

Since, the chains are soo long, it will take a long time to be used up, rather than glucose, which incorporated itself directly. So, one fatty acid chain provides more energy, therefore takes longer time to be used up.

*Please correct me if I am wrong, this makes sense to me!!

Not at all saying you are wrong but do you mind "citing" where you got that information? I would like to learn more about it.

Thanks.

 

[poc91nc]

If you're interested in that stuff....check your undergraduate library for a copy of Voet and Voet Biochemistry. Everything you ever wanted to know about metabolism but were afraid to ask.

 

[shamrock2006]

any biochem book should answer this question nicely...at least mine does/did.

 

[DailyDrivenTJ]

Thanks guys. Never taken biochemistry before. Sorry for the OT, So out of curiosity, what is the class about? Bio and chemistry combined in depth?

 

[Streetwolf]

The chemistry of biological processes.

Also it's so hard to lose fat because the body makes it hard to lose it. We learned this in my diet/health class recently. It takes a loss of about 3500 kcal to lose 1 pound. The normal diet is probably near 2000 kcal so if you trimmed off 200 or so kcal from your diet per day and exercised off another 300 kcal per day, you could lose 1 pound per week. But also, your body will try to 'protect' itself from losing the weight. If you do succeed, you have to keep up the good workout regimen. If you don't, you will easily gain back the weight and find it harder to lose the same amount the next time around.

 

[ingemar]

One of the reasons why it is hard to lose excess fat is because once the body creates and fills fat cells, you'll keep them for good. When your body burns fat, the fat stores in the cells are depleted, but the actual cells remain. There is no reason for your body to quickly get rid of these cells, especially if you are trying to lose weight, as your body will want to store as much fat as possible (an efficient waterless way of storing energy). This makes it very easy for your body to put on fat again, and very hard to get rid of excess fat. An example of where excess fat cells makes losing excess fat difficult is in hyperplasia of fat cells.

 

[pre-dentalguy]

Is it because we have to use energy to hydrolyze fat to glycerol and fatty acids and then use energy to convert them to intermediates in cellular respiration??

Many scientists suggest that whenever you try to lose weight by severely cutting back on calories (particularly if the cutback is drastic) your body sees the caloric reduction as a famine. It responds by going into survival mode. It slows down the basic processes of day-to- day living and the body’s tissues to get some of the additional energy (calories) it believes it needs. Unfortunately, it doesn’t turn to the fat cells for that extra energy/Instead, it first breaks down some of your muscle tissue, and that’s bad.

Muscle cells, unlike fat cells, are active; they actually work. The mitochondria of muscle cells are like little energy plants - they are responsible for burning many of the calories we take in each day. The more muscle tissue you have, the more efficiently you burn calories. Conversely, when you lose muscle tissue, you lose some of your body’s ability to burn calories. When the body uses up muscle tissue to compensate for the “starvation” of dieting, it accomplishes two tasks at once. It gets extra energy but it also slows down your metabolism.

The fact is, you can’t trick your body into becoming permanently thin by temporarily depriving it of food. It’s too smart to fall into that trap. It is the descendant of millions of other bodies that survived true starvation - famines far worse than anything you could impose while on a diet. As far as your body is concerned, it has one job: to keep alive and to keep those fat cells filled up and ready for the next time the food supply runs out. And there is some evidence that the more you diet, the better your body gets at its job.

- Marion

 

[PrincessDMD]

Might be kind of off topic, but does your body breakdown FAT first or Protiens first in a state of starvation?? When you starve your body it first breaks down carbs, then
I think its protiens but some people think its fats..

 

[PrincessDMD]

Might be kind of off topic, but does your body breakdown FAT first or Protiens first in a state of starvation?? When you starve your body it first breaks down carbs, then
I think its protiens but some people think its fats..

 

[Streetwolf]

Muscle, sadly

(protein)

 

[BodybldgDoc]

60% muscle + 40% fat in a state of starvation that is