L-C

Fat and glucose vs. fructose

119 posts in this topic

Here is a pretty long lecture by one Robert Lustig, MD, on why neither fats nor carbohydrates in general, but rather fructose (as present in sugar, i.e. sucrose, or HFCS) is responsible for the increased incidence of cardiovascular problems and obesity:

I believe I read a post of RayK's (that I'm unable to find at the moment) where he stated that the body does not distinguish between different forms of carbohydrates. This contradicts Lustig's argument that glucose is okay but fructose, much like alcohol, has to be handled by the liver which leads to fat storage and other problems even on a caloric maintenance diet. Personally, I find RayK's argument from the position of evolution compelling.

I couldn't with good conscience ask people to view the entire 1.5 hour video but perhaps you've encountered the same argument in a more condensed form? He does use biology to support his argument, but I'm not capable of judging its veracity, nor whether it ultimately amounts to anything in the context of human physiology.

One of the things he brings up is the high availability of sucrose without the accompanying dietary fiber, that is refined sugar/HFCS, otherwise found in fruits. I'd be interesting to hear your views on this.

Share this post


Link to post
Share on other sites

There is no logical reason to avoid any form of carbohydrates to include sugars of which fructose is. Ther are three types of carbohydrates; sugars, starches and fibers. All carbohydrates are made up of a certain number of sugar blocks. Sugar blocks can be single blocks, double blocks or many blocks connected together in long chains. All carbohydrates have about the same number of calories although they do vary in their chemical structure and number of units/sugar blocks that make them. Sugars are made up of only one or two sugar blocks and this is why they are called simple carbohydrates. Starches and fibers are made up of many sugar blocks that are connected together and why they are called complex carbohydrates.

Within the simple carbohydrates there are six main sugars. Three of those are single sugars called monosaccharides which are:

Glucose

Fructose

Galactose

The double sugar blocks are called disaccharides which are:

Maltose (glucose + glucose)

Sucrose (glucose + fructose)

Lactose (glucose + galactose)

Fructose (which like so many of the other sugars has been falsely condemned for years) is the sweetest tasting sugar. Fructose along with Glucose are what make up Sucrose which is what makes up basic table sugar. Fructose also occurs naturally in items such as fruits, berries, vegetables and honey.

Complex carbohydrates (starchs and fibers) are found in plants and their structure is composed of straight or branched chains of 10 or more sugar blocks called polysaccharides. Like the other digestable carbohydrates when we eat starchs they are converted into glucose and then used for fuel. Fiber also comes from plant foods and cannot be digested by the human digestive system. Fibers are called nonstarch polysaccharides which are made up of cellulose, hemicellulose, pectins, gums, mucilages and lignins. Fiber is what gives plants their structure and is found in all plants. And unlike the two other forms of carbohydrates it cannot be broken down as humans do not have the enzymes needed to do so. If a person ate only fiber they would probably starve to death as the tiny amount of calories that our digestive tract gets from dealing with fiber is not enough to support a human life although it does have some benefits.

Overall, sugars do not cause health problems when eaten in rational amounts. In other words, there is no direct relationship between carbohydrate/sugar intake and health problems such as obesity, hyperactivity, diabetes or heart disease. Sugars, like any form of energy can cause weight gain and lead to obesity if to many calories are eaten. As a matter of fact many studies have documented that obese people eat less sugar than thin people. In studies done for almost fifty years the American Diabetes Association, along with a few other researchers in this field, found that there was almost no scientific evidence to suggest that sugar is more quickly digested and absorbed into the bloodstream than starchs, nor that sugar elevates blood gluscose more than starchs. Sugar was also found to have about the same effect on blood glucose as any other carbohydrate.

Share this post


Link to post
Share on other sites

Thanks for the reply. So, basically, Lustig is wrong and his diagrams are either false or do not apply?

Also, I gather that, regarding diet, amount is much more important than kind. Not to the degree that eating 2000 calories of white sugar a day is equal to 60/20/20 of real food, but closer than people like him would have you think.

Share this post


Link to post
Share on other sites
[...]I'd be interesting to hear your views on this.

The nutritionists, Dirk Pearson and Sandy Shaw, co-authors of Life Extension, should be included in the discussion.

I'm not an expert on the matter, however, there appear to be several essential concepts that have been left out of the discussion.

For example: refined carbohydrates, complex carbohydrates, insulin levels, blood sugar levels, insulin cause of fat, HGH, human growth hormone, human growth hormone releasers, arginine, orthinine, calories, fat:muscle:bone mass ratios, and exercise.

Inventor

Share this post


Link to post
Share on other sites
[...]I'd be interesting to hear your views on this.

The nutritionists, Dirk Pearson and Sandy Shaw, co-authors of Life Extension, should be included in the discussion.

I'm not an expert on the matter, however, there appear to be several essential concepts that have been left out of the discussion.

For example: refined carbohydrates, complex carbohydrates, insulin levels, blood sugar levels, insulin cause of fat, HGH, human growth hormone, human growth hormone releasers, arginine, orthinine, calories, fat:muscle:bone mass ratios, and exercise.

Let us start with the first example, refined carbohydrates. The definition of a refined carbohydrate is a food that has been processed by machinery that strips away the bran and germ. The process gives foods a finer texture and prolongs shelf life. The process also removes some nutrients such as B vitamins, but this really does not matter as the carbohydrate, whether bread, rice or pasta, is later enriched with vitamins and minerals. And if one is worried about missing out on the fiber from the bran they can add fiber (which as I mentioned earlier are non-digestable carbohydrates) to their sandwich or eat a salad with their spaghetti or rice.

Maybe that information can be taken to the so called "experts" the next time they try and scare people away from certain foods.

And just as an added bonus, sugar substitutes act like fiber as they are undigestable and pass through the human digestive system acting like "roughage" by pushing things out. And just like fiber, when a person ingest to much sugar-substitue they will end up with runny bowel movements. On second thought, that information is not a bonus. ;)

Share this post


Link to post
Share on other sites

Ray,

What do you think of the effects of the various food groups with regard to (1) the feeling of hunger (or of satisfied hunger), (2) calories ingested per a given volume of food?

I have tried to removed starches and sweetened food from my diet, and I have lost weight, and I suspect that it's because both starches and sweets are rich in calories compared to how well they satisfy hunger.

Share this post


Link to post
Share on other sites
Ray,

What do you think of the effects of the various food groups with regard to (1) the feeling of hunger (or of satisfied hunger), (2) calories ingested per a given volume of food?

I have tried to removed starches and sweetened food from my diet, and I have lost weight, and I suspect that it's because both starches and sweets are rich in calories compared to how well they satisfy hunger.

The intake of carbohydrates and fats both cause the release of two different hormones (carbohydrates/Serotonin and fat/Cholecystokinin) that shut down the hunger urge within the hypothalamus gland. Protein intake also causes the release of Cholecystokinin, but in such small amounts that it never leaves the stomach and only helps in the metabolism of protein. A low amount of carbohydrates in one's diet causes a reduction in the output of Serotonin and an increase urge for sugar of which once begun usually ends with an over intake of carbohydrates/sugar. The same thing applies to fat and the production and release of Cholecystokinin. "Nature, to be commanded, must be obeyed."

You have most likely, like every other human, lost weight because you discarded all the calories that come in that food group. I guarantee that if you cut out a whole food group, whether proteins, fats or carbohydrates, you are going to lose weight, but it is not something that needs to be done.

Share this post


Link to post
Share on other sites

Just to be clear, I didn't cut out carbs. I just cut out starchy foods (grains, bread, legumes, rice, pasta,...) and sweetened foods (basically, desserts or sweet snacks). I'm eating plenty of fruits and veggies.

Share this post


Link to post
Share on other sites
Just to be clear, I didn't cut out carbs. I just cut out starchy foods (grains, bread, legumes, rice, pasta,...) and sweetened foods (basically, desserts or sweet snacks). I'm eating plenty of fruits and veggies.
But why would you need to, if the goal is simply to lose some weight? I didn't cut out anything; I just reduced the amount I ate. Now, I was never big eater of sweet things, but I do enjoy a bit of dessert on occasion. One trick that has worked well for me is to use smaller plates and bowls. Something to consider, if portion size is an issue.

Share this post


Link to post
Share on other sites
Just to be clear, I didn't cut out carbs. I just cut out starchy foods (grains, bread, legumes, rice, pasta,...) and sweetened foods (basically, desserts or sweet snacks). I'm eating plenty of fruits and veggies.

And just to be clear, once again, all carbs average the same amount of calories per gram (which is 4) and your metabolism/digestive system processes them ALL in the same manner and in about the same amount of time. In other words, simple carbs and complex carbs are all turned into glucose and if we eat to many of any form or carbs they will be converted into fat, and the same thing happens when we eat to much protein and to much fat. So, once again, your weight loss does not surprise me as you cut out all the calories that came within those foods that you cut out of your diet.

"Nature, to be commanded, must be obey." When someone can show me that the nature of man has changed, and specifically human metabolism has changed how it processes caloires (kilo-calories/heat/energy), then I will rethink my premise. So, once again, I offer that people study the nature of man as a whole and then seperate away the specific systems, such as the digestive system, the endocrine system, the neurological system, the cardio-vascular system, the muscle-skeleton system so one can grasp a deeper understanding into what man's biological nature is.

Share this post


Link to post
Share on other sites

Jason - it simply works better for me, at least for now. Maybe I simply find it easier to change the nature of what I eat than the overall quantity. I'm eating as much or more than I used to, and much more meats and fat - but less sugar. One thing I've noticed is that if I now eat a meal rich in starch & sugar, I feel pretty bad for a few hours afterward. This is purely anecdotal, however.

Share this post


Link to post
Share on other sites
Jason - it simply works better for me, at least for now. Maybe I simply find it easier to change the nature of what I eat than the overall quantity. I'm eating as much or more than I used to, and much more meats and fat - but less sugar. One thing I've noticed is that if I now eat a meal rich in starch & sugar, I feel pretty bad for a few hours afterward. This is purely anecdotal, however.
I reckon that you choose the things that you enjoy if that's what motivates you. I personally never feel ill after effects of the foods I eat, so I saw no need to change what I ate, but I did need to reduce the amount if I wanted to lose the weight. I do notice that I no longer can eat the volume I used to. For example, on a Saturday or Sunday morning, I might go downstairs to my local cafe for some eggs and bacon. I can now finish about half the portion they serve, whereas before I had no trouble eating the whole thing.

Share this post


Link to post
Share on other sites
Fructose (which like so many of the other sugars has been falsely condemned for years) is the sweetest tasting sugar. Fructose along with Glucose are what make up Sucrose which is what makes up basic table sugar. Fructose also occurs naturally in items such as fruits, berries, vegetables and honey.

Could you supply a reason why Lustig is wrong on the particular type of metabolism the liver performs on fructose and its effects?

Also can you point me to a study on the non leptin satiating hormones please.

Share this post


Link to post
Share on other sites
One thing I've noticed is that if I now eat a meal rich in starch & sugar, I feel pretty bad for a few hours afterward. This is purely anecdotal, however.

I'm like that too. If I have sugar I immediately get high and then crash. I have always felt so bad that I never developed a liking for candy or pastries.

I had a 4-hour glucose tolerance test and it showed that when I ingest a large amount of simple carbs, my insulin immediately spikes and then my blood sugar level crashes. That accounts for how I feel. Most people don't react that way, but I do and so do people with type 2 diabetes. I have never been diabetic because my blood sugar and Hb1ac levels have always been well within the normal range, but I do overreact to refined carbs. As a result, my doctor put me on a low-glycemic diet for my health and weight control and it doesn't seem like a "diet" at all. It is full of my favorite foods -- meats, fruits, vegetables -- and eliminates sugars and simple starches which I never liked much anyway.

Share this post


Link to post
Share on other sites

Anytime a normal person eats more than 500 calories at one time their pancreas release extra amounts of insulin to deal with the extra glucose that is now flowing through the blood stream. Usually after the large release of insulin (insulins primary function is to regulate blood-glucose levels) the insulin takes to much glucose out of the blood stream and hence the so called "crash," this is normal to everyone and not just Betsy. It also happens when people take in to much after protein and fat, of which turkey dinners at Thanksgiving time are known for.

Share this post


Link to post
Share on other sites
Anytime a normal person eats more than 500 calories at one time their pancreas release extra amounts of insulin to deal with the extra glucose that is now flowing through the blood stream. Usually after the large release of insulin (insulins primary function is to regulate blood-glucose levels) the insulin takes to much glucose out of the blood stream and hence the so called "crash," this is normal to everyone and not just Betsy. It also happens when people take in to much after protein and fat, of which turkey dinners at Thanksgiving time are known for.

Further, fructose does not trigger the pancreas to release insulin as it is sent to the liver where almost all of its metabolizing takes place, unlike the other forms of sugars. In other words, the sugar fructose taken in by itself does not cause an increase in insulin production and release, so no "crash" comes from the drop-off of glucose in the blood stream.

Share this post


Link to post
Share on other sites
Anytime a normal person eats more than 500 calories at one time their pancreas release extra amounts of insulin to deal with the extra glucose that is now flowing through the blood stream. Usually after the large release of insulin (insulins primary function is to regulate blood-glucose levels) the insulin takes to much glucose out of the blood stream and hence the so called "crash," this is normal to everyone and not just Betsy. It also happens when people take in to much after protein and fat, of which turkey dinners at Thanksgiving time are known for.

Further, fructose does not trigger the pancreas to release insulin as it is sent to the liver where almost all of its metabolizing takes place, unlike the other forms of sugars. In other words, the sugar fructose taken in by itself does not cause an increase in insulin production and release, so no "crash" comes from the drop-off of glucose in the blood stream.

Unless, of course, like anything we eat in excess. If we take in to many calories from fructose or any other form of food, the liver will, at some point, convert that energy source into fat.

Share this post


Link to post
Share on other sites
Fructose (which like so many of the other sugars has been falsely condemned for years) is the sweetest tasting sugar. Fructose along with Glucose are what make up Sucrose which is what makes up basic table sugar. Fructose also occurs naturally in items such as fruits, berries, vegetables and honey.

Could you supply a reason why Lustig is wrong on the particular type of metabolism the liver performs on fructose and its effects?

Also can you point me to a study on the non leptin satiating hormones please.

How technical do you want to get? Do you have a good understanding of human metabolism?

And I am sure you can google your request on hormones as well as I can. But, I offer that you first gain a fundamental understanding of the biological nature of man, specifically man's metabolism, if you do not already have one.

Share this post


Link to post
Share on other sites
Fructose (which like so many of the other sugars has been falsely condemned for years) is the sweetest tasting sugar. Fructose along with Glucose are what make up Sucrose which is what makes up basic table sugar. Fructose also occurs naturally in items such as fruits, berries, vegetables and honey.

Could you supply a reason why Lustig is wrong on the particular type of metabolism the liver performs on fructose and its effects?

Also can you point me to a study on the non leptin satiating hormones please.

How technical do you want to get? Do you have a good understanding of human metabolism?

And I am sure you can google your request on hormones as well as I can. But, I offer that you first gain a fundamental understanding of the biological nature of man, specifically man's metabolism, if you do not already have one.

As technical as you think is needed to counter Lustigs actual points. Im sure I can follow you.Keep in mind Lustig is challenging certain "fundamental" assumptions.

Share this post


Link to post
Share on other sites
Fructose (which like so many of the other sugars has been falsely condemned for years) is the sweetest tasting sugar. Fructose along with Glucose are what make up Sucrose which is what makes up basic table sugar. Fructose also occurs naturally in items such as fruits, berries, vegetables and honey.

Could you supply a reason why Lustig is wrong on the particular type of metabolism the liver performs on fructose and its effects?

Also can you point me to a study on the non leptin satiating hormones please.

How technical do you want to get? Do you have a good understanding of human metabolism?

And I am sure you can google your request on hormones as well as I can. But, I offer that you first gain a fundamental understanding of the biological nature of man, specifically man's metabolism, if you do not already have one.

As technical as you think is needed to counter Lustigs actual points. Im sure I can follow you.Keep in mind Lustig is challenging certain "fundamental" assumptions.

First off, I do not care to counter his argument and while watching the first 30 minutes of the video I did not see any "fundamental" challenges put forth. But, I can explain how humans metabolize fructose.

When fructose is taken into the body, which for the most part is in the form of sucrose which is a combination of fructose with glucose it is hydrolysed by sucrase in the intestinal cell, forming glucose and fructose. Fructose, unlike glucose, is able to enter muscle cells and when to many calories are taken in at one time fructose can also enter adipocytes (fat cells). Both events can happen even in the absence of insulin by using glucose transporter (Glu T5).

Fructose enters the liver via the fructose transporter, Glu T5. Then the liver enzyme fructokinase phosphorylates fructose 1-phosphate. This is cleaved by fructose 1-phosphate aldolase (aldolase B ) to form dihydroxyacetone phosphate and glyceraldehyde. Glyceraldehyde is then phosphorylated to triose kinase to glyceraldehyde 3-phosphate. Then the intermediary metabolites of fructose enter glycolysis as triose phosphates. From this point, what will happen next depends on the individual's metabolic status. In normal situations, it is most likely that gluconeogenesis will happen and either glycogen or glucose will be formed, or if to many calories are taken it at one time the energy will be converted and stored in adipocytes (fat cells).

It is also likely that when normal amounts of fructose are presented to the liver in the portal blood it will be converted to glucose or hepatic glycogen. This means that little amounts of fructose will remain for mteabolism by muscle. But what ever amounts of fructose do remain they are metabloized to fructose 6-phosphate by hexokinase, since fructokinase is absent from muscle. Once again, the fate of fructose 6-phosphate depends on the individual's metabolic status which determines whether it is converted to glycogen or used as respiratory fuel.

I also have more than 30 years of weight training and research behind me, more than 20 years of training other people and recording their outcomes/progress. I have also been in business for more than 10 years where I have been educating people on the fundamentals of a rational diet along with all their "real world" progress to back my conclusions. Every person/client that I have educated/trained that applies the fundamentals I teach them loses weight, gains lean-body tissue, while also enhancing all their other medical markers.

Share this post


Link to post
Share on other sites
Anytime a normal person eats more than 500 calories at one time their pancreas release extra amounts of insulin to deal with the extra glucose that is now flowing through the blood stream. (...) It also happens when people take in to much after protein and fat, of which turkey dinners at Thanksgiving time are known for.

Why is this mechanism triggered if the meal contains little sugar?

Share this post


Link to post
Share on other sites

Ray, have you ever heard of Covert Bailey? Back around 1990 he was giving nutritional lectures to packed ( shown on TV) audiences in a very amusing manner. I thought he made a lot of sense, and wonder what you thought of him.

Share this post


Link to post
Share on other sites
Anytime a normal person eats more than 500 calories at one time their pancreas release extra amounts of insulin to deal with the extra glucose that is now flowing through the blood stream. (...) It also happens when people take in to much after protein and fat, of which turkey dinners at Thanksgiving time are known for.

Why is this mechanism triggered if the meal contains little sugar?

When proteins are ingested into the body they are digested by gastric intestinal proteolytic enzymes to form amino acids. These newly formed amino acids are absorbed into the blood stream and transported to the liver. The human body (unlike what most people think) can only use a certain amount of protein at one time which for the most part is around 30 grams. A normal sized male only requires around 68 grams of protein a day to not only maintain but also build new muscle through protein synthesis. If someone eats a large amount of protein, such as what is being recommended through high protein intake diets, then the excess can be converted into glucose through the process of gluconeogenesis and then sent back into the blood stream where it is either used (such as for the brain's energy source), stored in the muscle in the form of glycogen or sent back to the liver and converted into triacylglycerol and then stored in adipocytes (fat cells) as fat. Also, some of the excess protein/amino acids do not leave the liver as glucose and in accordance to an individuals metabolic status they can be quickly turned to fat and stored in the adipocyte. So, as I have mentioned many times before, insulin is released anytime we eat and not only when we eat just carbs.

There are other negative effects from taking in to much protein of which one is created through the deamination of excess amino acids (the broken down form of protein) and causes the build-up of ammonia which is toxic to humans. Under normal circumstances the ammonia can be converted in the liver to the non-toxic urea and excreted from the body in the urine. But when excessive amounts of protein are taken in the liver cannot process the ammonia fast enough and uric acid builds in the body which causes gout. Also, when there is a toxic build-up of acid that the kidneys and liver cannot process it leads to acidosis which can lead to coma or death.

Share this post


Link to post
Share on other sites
Fructose, unlike glucose, is able to enter muscle cells and when to many calories are taken in at one time fructose can also enter adipocytes (fat cells).

There are some suggestions made that the difference between glucose and fructose is not so insignificant (and even the fact mentioned above may be of some importance).

It has to do with the hormone Leptin (more specifically condition called Leptin resistance):

Fructose and Leptin

Share this post


Link to post
Share on other sites