The Science Behind Atkins - Weight Loss Message Board

RKYDDS · 11-23-2003, 01:10 PM

Alot of people are curious about how Atkins works and I figured I would make a brief summary of the certain biochemical reactions that are involved in the effectiveness of the Atkins diet or any low carb diet for that matter. Mind you many of these biochemical rections have recently been uncovered so it will go against traditional methods of thinking...

There are many enzymes involved in the synthysis of fatty acids that are stored in your body as "ugly fat" I will not go through every biochemical reaction because that would take all day and hundreds of boring pages.

The enzyme that Low Carb Diets seem to target is called Acytyl-CoA carboxylase. This enzyme is responsible for converting Acytyl-CoA into Malonyl-CoA. Malonyl-CoA is the molecule NECESSARY for the production of fatty acids.

Now think of Acytyl-CoA as the one big crossroad for all your body's metobolic reactions from this point given differing conditions almost anything can be syntysized from this molecule. The purpose of low carb diets is to shunt Acytyl-CoA AWAY from fatty acid synthysis and INTO other metobolic pathways.

I will try to explain the chemical reactions given a set of 2 scenarios:

Scenario 1: Low Carb High Fat Diet...

When your body is in a low carb state a substance called glucogon is secreted from your pancreas. When you consume many fatty acids in your diet it's digestion produces what is called Fatty-ACYL-CoA. These two INHIBIT the production and activation of Acytyl-CoA carboxylase... this means no Malonyl-CoA is produced and thus NO FAT PRODUCTION IS POSSIBLE.

Long term exposure to this diet will eventually make the body produce LESS Acytyl-CoA carboxylase and thus gentically speaking you will be less apt to store fat.

Scenario 2: High Carb Low Fat Diet...

When your body is in a high carb state a substance called insulin is secreted from your pancreas. Also when no fat is consumed there is a decreased level of Fatty-ACYL-CoA. This means Acytyl-CoA carboxylase is HIGHLY ACTIVE it will turn the Acytyl-CoA into Malonyl-CoA and into fat at a rapid rate.

Additonaly long term exposure to this diet will cause you body to produce MORE Acytyl-CoA carboxylase and thus it will accelerate fat production.

So essentally a Low Fat High Carb Diet is biochemically speaking the BEST WAY TO GAIN WEIGHT and the only way to loose weight using one of these diets is to inhibit food intake to a level that constitutes moderate starvation...

Food for thought...

Also if you want to know how excersise plays a role in weight loss it also targets the same enzyme... Prolonged periods of excersise not only burns calories and keeps you in shape it also results in the production of AMP-dependant protien kinase (AMPK) which INHIBITS Acytyl-CoA carboxylase which of course means less fat is produced...

VTBoy916 · 11-23-2003, 01:33 PM

Quote:

Originally Posted by RKYDDS

Alot of people are curious about how Atkins works and I figured I would make a brief summary of the certain biochemical reactions that are involved in the effectiveness of the Atkins diet or any low carb diet for that matter. Mind you many of these biochemical rections have recently been uncovered so it will go against traditional methods of thinking...

There are many enzymes involved in the synthysis of fatty acids that are stored in your body as "ugly fat" I will not go through every biochemical reaction because that would take all day and hundreds of boring pages.

The enzyme that Low Carb Diets seem to target is called Acytyl-CoA carboxylase. This enzyme is responsible for converting Acytyl-CoA into Malonyl-CoA. Malonyl-CoA is the molecule NECESSARY for the production of fatty acids.

Now think of Acytyl-CoA as the one big crossroad for all your body's metobolic reactions from this point given differing conditions almost anything can be syntysized from this molecule. The purpose of low carb diets is to shunt Acytyl-CoA AWAY from fatty acid synthysis and INTO other metobolic pathways.

I will try to explain the chemical reactions given a set of 2 scenarios:

Scenario 1: Low Carb High Fat Diet...

When your body is in a low carb state a substance called glucogon is secreted from your pancreas. When you consume many fatty acids in your diet it's digestion produces what is called Fatty-ACYL-CoA. These two INHIBIT the production and activation of Acytyl-CoA carboxylase... this means no Malonyl-CoA is produced and thus NO FAT PRODUCTION IS POSSIBLE.

Long term exposure to this diet will eventually make the body produce LESS Acytyl-CoA carboxylase and thus gentically speaking you will be less apt to store fat.

Scenario 2: High Carb Low Fat Diet...

When your body is in a high carb state a substance called insulin is secreted from your pancreas. Also when no fat is consumed there is a decreased level of Fatty-ACYL-CoA. This means Acytyl-CoA carboxylase is HIGHLY ACTIVE it will turn the Acytyl-CoA into Malonyl-CoA and into fat at a rapid rate.

Additonaly long term exposure to this diet will cause you body to produce MORE Acytyl-CoA carboxylase and thus it will accelerate fat production.

So essentally a Low Fat High Carb Diet is biochemically speaking the BEST WAY TO GAIN WEIGHT and the only way to loose weight using one of these diets is to inhibit food intake to a level that constitutes moderate starvation...

Food for thought...

Also if you want to know how excersise plays a role in weight loss it also targets the same enzyme... Prolonged periods of excersise not only burns calories and keeps you in shape it also results in the production of AMP-dependant protien kinase (AMPK) which INHIBITS Acytyl-CoA carboxylase which of course means less fat is produced...

Reports have shown much of what you say to be untrue. They have done test that proved that for weight loss all that really matter is how many calories you eat. They have done studies where one group was on a low carb diet and the other was on low fat high carb diet. They both ate the same amount of calorie and in the end they LOST THE SAME AMOUNT OF WEIGHT. It has been proven time and time again all that really matter is how much you put in vs how much you burn.

RKYDDS · 11-23-2003, 01:42 PM

Quote:

Originally Posted by VTBoy916

Reports have shown much of what you say to be untrue. They have done test that proved that for weight loss all that really matter is how many calories you eat. They have done studies where one group was on a low carb diet and the other was on low fat high carb diet. They both ate the same amount of calorie and in the end they LOST THE SAME AMOUNT OF WEIGHT. It has been proven time and time again all that really matter is how much you put in vs how much you burn.

I can find and have read studies that say both... The funny thing about studies is they can be confounded depending on what is done and how low is low...

In order for Low Carb diets to work the level of carb intake must be low enough... Many people have diffrent definitions of low carb...

Atkins says 20 grams... Which is low enough to shunt Acytyl-CoA away from fatty acid synthysis.

100 grams a day is pretty low but not enough to shunt Acytyl-CoA away from fatty acid synthysis. The studies you have read most likey instituted carb intakes higher than threshold levels.

I can only say that thats what happens biochemicaly and biochemically it makes sense.

Examples of studies that had instituted carb levels which were in fact "low enough" is the highly publicized DUKE study... [url]http://www.dukehealth.org/news/healthbrief_july02_3.asp[/url]

[url]http://www.usatoday.com/news/health/2002-11-18-adkins_x.htm[/url]

This article can also be found in the july 2002 New England Journal of Medicine...

Also a U-Penn Study... [url]http://content.nejm.org/cgi/content/abstract/348/21/2082?andorexacttitleabs=and&search_tab=a rticles&tmonth=Nov&searchtitle=Articles& sortspec=Score+desc+PUBDATE_SORTDATE+des c&excludeflag=TWEEK_element&hits=20&wher e=fulltext&tyear=2003&andorexactfulltext =and&fyear=1993&fmonth=Nov&searchterm=at kins&searchid=1069621342490_7351&FIRSTIN DEX=0&journalcode=nejm[/url]

Of course there will always be doubters but new discoveries in medicine and biochemistry proves that this is in fact what happens... now more than ever the evidence is piling up against a calorie is a calorie... mentality...

VTBoy916 · 11-23-2003, 02:37 PM

Quote:

Originally Posted by RKYDDS

I can find and have read studies that say both... The funny thing about studies is they can be confounded depending on what is done and how low is low...

In order for Low Carb diets to work the level of carb intake must be low enough... Many people have diffrent definitions of low carb...

Atkins says 20 grams... Which is low enough to shunt Acytyl-CoA away from fatty acid synthysis.

100 grams a day is pretty low but not enough to shunt Acytyl-CoA away from fatty acid synthysis. The studies you have read most likey instituted carb intakes higher than threshold levels.

I can only say that thats what happens biochemicaly and biochemically it makes sense.

Examples of studies that had instituted carb levels which were in fact "low enough" is the highly publicized DUKE study... [url]http://www.dukehealth.org/news/healthbrief_july02_3.asp[/url]

[url]http://www.usatoday.com/news/health/2002-11-18-adkins_x.htm[/url]

This article can also be found in the july 2002 New England Journal of Medicine...

Also a U-Penn Study... [url]http://content.nejm.org/cgi/content/abstract/348/21/2082?andorexacttitleabs=and&search_tab=a rticles&tmonth=Nov&searchtitle=Articles& sortspec=Score+desc+PUBDATE_SORTDATE+des c&excludeflag=TWEEK_element&hits=20&wher e=fulltext&tyear=2003&andorexactfulltext =and&fyear=1993&fmonth=Nov&searchterm=at kins&searchid=1069621342490_7351&FIRSTIN DEX=0&journalcode=nejm[/url]

Of course there will always be doubters but new discoveries in medicine and biochemistry proves that this is in fact what happens... now more than ever the evidence is piling up against a calorie is a calorie... mentality...

What about Atkins idea that a carb is just a carb. The UCSF has done study that showed when people went from a normal diet to a vegeterian diet without lowering there calorie intake, they lost a larg amount of weight even though they ate the same calories. These people got nearly all of there calories from carbs. This shows what you say may infact be wrong. So your idea that a high carb diet causing you to get fat is has been shown to be wrong. Studies have shown that the most healthy diet may infact be a vegiterian diet. When I say vegiterian I mean a near zero fat diet where most of your calories come from fruits and vegies.

RKYDDS · 11-23-2003, 02:51 PM

Quote:

Originally Posted by VTBoy916

What about Atkins idea that a carb is just a carb. The UCSF has done study that showed when people went from a normal diet to a vegeterian diet without lowering there calorie intake, they lost a larg amount of weight even though they ate the same calories. These people got nearly all of there calories from carbs. This shows what you say may infact be wrong. So your idea that a high carb diet causing you to get fat is has been shown to be wrong.

Ahh but a carb is not a carb... this is the basis behind the south beach diet.... I dont think atkins has ever stated that a carb was just a carb...

Depending on the type of carb there is a glycemic index for every type of carb.

A high glycemic index means that the food can be digested quickly and broken down into glucose quickly... this means that insulin levels will spike and when insulin levels spike we get an INCREASED activity in Acytyl-CoA carboxylase.

Foods with lower glycemic indexes break down slower and thus causes less of an insulin spike. Less insulin means less Acytyl-CoA carboxylase activity which means less fat synthysis.

Consequently foods with lower glycemic indexes tend to be "healthier" foods. Such as beans and veggies and friuts.

The kicker is that Fruits which are high in fructose bypass the enzyme Phosphopofructokinsase-1 (PFK-1) this enzyme intitiates a regulatory step that increases insulin. Thus Fructose is less likely to spike insulin levels that processed carbohydrates.

Like there is more than one way to kill a chicken biochemically there is more than one way to loose weight

I think the trick in following this kind of diet is to stay away from simple sugars and processed carbs.

Biochemically a low glycemic diet also makes sense

I hope I have your understanding.

This study you bring up further proves that a calorie is not a calorie... generally speaking weight loss biochemistry today seems to revolve around the regulation of the enzyme Acytyl-CoA carboxylase.

In order for me to further decipher the study i must know how many calories were consumed as I stated before you can loose weight on a high carb diet IF you consume so little calories that you body goes into moderate starvation.