View Full Version : How does sugar make you fat?

04-16-2001, 12:46 PM
Ok, i've been wondering this for a while now.

I know that complex carbs take longer for the body to convert into glucose, thus give a more sustained energy release. Why would that matter in terms of sugar causing fat gain? The end result is glucose either way. I understand that complex carbs are better for energy, but i don't see why they don't cause fat gain as easily.

Sorry if this is unclear...I'm in a rush.

04-16-2001, 01:08 PM
Calories in VS Calories out.

04-16-2001, 01:37 PM
1. total calories
2. easy path to energy prevents fat metabolism (more)

Simple sugars give you an instant energy thus in the time immediately following sugar intake, your body stores any excess calories as fat VERY QUICKLY.

In contrast, complex carbohydrates take time to digest and while they do end up as simple sugars, if you eat balanced meals, you don't get the same sugar spike rather a steady level of glucose over time.

If you ate small quantities of sugar throughout the day then you would probably be fine but most of our sugar intake tends to be spikey (eg. 1 can of coke, a dessert, etc. etc.)

3. Question: I've wondered if there is any difference between simple sugars. eg. Honey vs Jam, Fructose vs Glucose

Podium Kreatin
04-16-2001, 01:55 PM
when ingesting sugar, it triggers insulin (a hormone which causes storage to parts of body) increase which cause the sugar to become fat. sugar is fairly simple (in terms of size) and doesn't take much energy to metabolize. complex carbs don't spike that much insulin, bc it's not easily absorbed as simple carbs

the different sugars from honey, jam, fructose, glucose, etc. are different in the terms of their chemical structure. fructose and glucose are both simplest, but have different chemical structures. to go even further, there are l-glucose and d-glucose, which have the same makeup, but different arrangements.
glucose(in blood) and dextrose(dietary glucose) are the same, and glycogen(blood/muscle) and maltodextrin(dietary) i think. carbs are either turned into glucose or glycogen (long chain of glucose)

the total cals intake over out/burned is true to some extent. ppl who don't normally do sports get fat bc they don't burn the sugar, but active atheletes burn a lot, so they don't usually get fat that easily. so that's concurrent evidence.
on the other hand, fat has a lot of cals, but take a lot of cals to metabolize (fat burns fat), but when taken with carbs (as most fatty foods do) the fat and carbs actually make u more fat than sugar/carbs alone.

the doc
04-16-2001, 03:43 PM
Ok heres the deal. ALL COMPLEX CARBS ARE TURNED TO SIMPLE SUGARS(mono-,di-, and tri- and IN THE DIGESTIVE TRACT. Complex carbs are simply polymers of simple sugars that are used mainly for energy storage (starch-glycogen) and structural scaffolds (like cellulose in plants). The saliva acid in your stomach begins the breakdown of complex carbs that greatly accelerates in the stomach, where the acid initiates the hydrolysis of complex carbs (starches) into simple carbs (sugars). This process happens quickly for some foods (white rice, mashed potato, and maltodextrin) and slowly for others (barley, black beans). This is where the GI comes in. GI measures (indirectly) the hydrolysis rate of these carbs into sugars and the insulin response. THe insulin response causes enzymatic and hormonal pathways to engage which do several things in the following "priorities", 1) fuel current energy requirements, 2) synthesis of glycogen(muscle and liver) for future use, and 3) synthesize triglycerides for energy storage (make fat). If you have no current energy needs(above that which to survive) and your glycogen stores are full, all of those carbs will be converted to fat. In the metabolic pathway, the conversion of glucose to pyruvate and finally acetyl CoA is irreversible and is dependant on the concentration of glucose (which is also where the idea that fat cannot be turned into sugar originates-due to the irrevisibility of the oxidation of pyruvate). THus the more glucose that enters your blood from any type of carb, the more stimulus there is to store it as fat. THe acetyl CoA formed is then assembled in the liver to fatty acids (Why is it not metabolized? this is because insulin shuts down the oxidation of acetyl CoA), triglycerides and then stored in the adipose tissue.

That is how carbs make you fat.

04-16-2001, 03:51 PM
................ K.

Azn Sensation
04-16-2001, 06:21 PM
Looks like the doc and podium know their shiet. They gave you some very good advice.

04-16-2001, 10:13 PM
Doc, I know why carbs make you fat, but i don't understand how sugar makes you fat, more than complex carbs make you fat.

The end result is glucose, either way. Complex carbs take longer to become glucose, thus give a more sustained energy release...i understand that part. I also understand the fact that when glyco stores are full, carbs have no where else to go except for fat stores. Why does sugar become fat easier than complex carbs become fat? I can understand that they may become fay quicker, but in the end wouldn't fat gain be the same?

04-17-2001, 01:29 AM
Well, simple carbs, i.e. sugars, are broken down more quickly than their complex bretheren. In turn, they cause the insulin to spike, and so if we dont expend that energy quickly, they are stored as fat.
If I eat a bowl of oatmeal and sit on my ass, I probably wont gain any fat because the energy is moderated and expended over a while, at about 70 calories per hour burned while sitting on said ass, in about two hours I will have spent all of those calories.
If I eat a few handfuls of sugar and then sit on my ass, even though I've eaten the same amount of calories as I would have if I had just eaten a bowl of oatmeal, the simple sugar carbs are already being stored as fat because I havent spent the energy quickly enough. The difference in weight gain is of course, that people with normal carb-based diets have metabolisms that favor burning carbs instead of fat. You are sitting on your ass, and instead of in the first example where you are burning the slowly-metabolized oatmeal, the sugar is being stored as fat.
The body will continue to burn calories, sure, but not necessarily the cals from the sugar because it is now fat. You'll also feel like utter crap after eating a handful of sugar.
We all know that the body holds onto fat like Rosie O'Donnell holds onto a meatball sub. That is the difference between fat gain with simple and complex carbs.
I think.

04-17-2001, 04:01 AM
Simple carbs DO NOT necessarily cause a greater insulin spike than complex carbs - and DO NOT necessarily cause more fat storage than complex carbs.

04-17-2001, 04:49 AM

the doc
04-17-2001, 07:23 AM
Yes to help coalesce what has been said here and to answer cackerot's question-
simple sugars (mono and disaccerides) in general will be absorbed into the blood much faster that complex carbs. However, some such as sucrose (table sugar), maltose (malts), and lactose (milk) and other of the 30 some monosaccerides that can exist must be first enzymaticly converted to glucose or other compounds that are metabolites of glucose. (this is how they are incorperated in carb metabolism). Thus they will not give as sharp an insulin increase as insulin in glucose dependant (mainly), and the consequences of that are mentioned above. Consider one who eats 1 cup of white rice and one cup of glucose. The glucose is swallowed and immediately starts being absored in the blood. All of this glucose is not absorbed at once, but rather is limited by the rate at which glucose can diffuse into the blood. This insulin response has been designated as 100. the one cup of white rice is chewed and mixed w/ saliva and IMMEDIATELY glucose is generated and is absorbed. The difference is that the digestion must occur for a few min to have glucose accumulate to the point where absorbtion becomes the limiting factor. This is why white rice has a slightly lower GI value than glucose, but this is really not significant.

My point here is that the supposition that sugars make you fat more that starches is just not correct. Also cack i believe you are right in that the end result is the same. I would caution though that extremely low GI stuff like barley and other tough to eat grains are an exception to this, because it takes soo long to digest and their carbs are not as accessable.

the doc
04-17-2001, 07:27 AM
Oh yea i forgot my favorite, maltodextrin, the ingredient in almost ALL MRP's. Maltodextrins are glucose polymers. THus they are complex carbs. Actually maltoDextrin has a greater GI than glucose-because it is a polymer, it has a higher nutrient density. It is so rapadily turned to glucose in the stomach that absorbtion immediately becomes rate limiting.

the take home point is that this complex carb has all the potential to make you fat, just as much as consuming glucose itself (actually a little more).

04-17-2001, 11:09 AM
The end result is not the same. Sugars cause a rapid spike in blood glucose, putting the pancreas in overdrive to produce insulin. MORE insulin is produced than needed as the pancreas plays "catch up" to the blood glucose levels, and excess insulin results in more sugars being stored as fat. Complex carbs DO NOT rapidly increase the blood glucose levels, so the pancreas only produces the NEEDED amount of insulin as the carbs are steadily metabolized.

04-17-2001, 12:58 PM
Well Gino, Honey ;) I'm not sure if that's entirely correct.

I do biology at college (i'm no scientist though) and i've been taught that when the pancreas releases insulin, it always realeases too much. Therefore, it releases glucagon to counteract the effects. The glucagon released is too much adn so insulin is released to counteract the effects. This cycle carries on until the blood sugar level is back to normal. It is called negative feedback.

I think this is right although it has been a while since i did Biochemistry...

04-17-2001, 01:56 PM
The issue is not the amount of simple sugars in sugar vs carbs.

The issue is the peak concentration of simple sugars in your system at any given time.

For the same reason that it is best not to binge and starve yourself, it is best to eat complex carbs as opposed to simple sugars as the latter tends to create the binge/starve effect.

Finally, most simple sugars offer no nutritional benefit as opposed to carbs which are usually packed with fibre and vitamins.

I hope this clears things up.

04-17-2001, 04:01 PM
Simple carbs DO NOT necessarily cause a greater insulin spike than complex carbs - and DO NOT necessarily cause more fat storage than complex carbs.

If you believe otherwise, you are wrong.

04-17-2001, 04:11 PM
I agree with Anthony the LoserBoy.

Any form of carbohydrates can cause an isulin increase. Infact, all do increase insulin release. Just some more than others.

04-17-2001, 07:53 PM
Chocolate is lower than brown rice on the G.I. scale.
So are you guys saying that chocolate doesn't necessarily have a higher chance of being stored as fat, as the brown rice does?


big calvin
04-17-2001, 09:10 PM
is the reason that alot of the complex carbs cause such a big insulin rush because it trys to stay in the blood steam and the pancreas is trying to push the glucose into storing? and that why some things that are simple sugars like fruit diesnt cause tht big of an insulin responce?

04-17-2001, 10:03 PM
Yes, let's just say that chocolate has lower G.I. But does that necessarly mean that it will get absorbed by ur body slower?...does that mean that it won't spike your insulin level?...

" The popular glycemic index is a measure of the speed at which carbohydrates enter the blood after a meal. A high-glycemic index means that blood sugar rises rapidly in response to a meal while a low-glycemic index means that blood sugar rises very slowly. Traditionally, nutritionists thought that the faster the carbs got into the blood, the bigger the insulin response. So in an attempt to manage insulin, they recommended always eating low-glycemic foods.
However, several studies since have shown that some low glycemic index foods have huge insulin responses! So the correlation between glycemic index and insulin response breaks down with some foods. For example, milk products have a very low glycemic index. But they promote insulin responses parallel to the highest glycemic foods. it appears that there are several other factors that determine insulin release besides carb content and the rate of carb absorption."

Glycemic Index only gives the glucose reponse to the meal but not the insulin response which is the "STORING" hornmone.. fats in the carb food will slow down the glucose response of your budy but you'll promote high blood levels of fats, carbs, and insulin...
IMO, the reason that chocolate is in the lower GI index is because of the fats in them. But it doesn't mean that it won't make you fat by spiking insulin or anything..
I dont know if i made sense here. i was trying to tie many things togather, so i may was just babbling non sense stuffs..

04-18-2001, 02:56 AM
Dabomber - sure there are other factors to how HIGH your insulin will increase ... probably the biggest factor is how MUCH of a certain food someone eats. Makes sense, right?

04-18-2001, 07:39 AM

We are talking about an insulin spike right? ie. a rapid increase and then a rapid decrease in insulin levels.

I am curious to learn more, could you provide some sources of information?


the doc
04-18-2001, 08:10 AM
I recommend any biochemistry text book. Or i saw something about -nutrition for dummies- these subjects may be well covered in there.

04-18-2001, 09:52 AM
I disagree Anthony. However, I don't believe I'm wrong. Why "necessarily" in both statements? Yes or no? Are there variables involved? You use the term greater - does this include "quicker?"

Chicken Daddy - you just said you agreed with Anthony, then made a statement that disagreed with anthony. Stop confusing us. lol

Yes, you are correct. ALL carbs trigger the release of insulin, and the pancreas (almost)always overcompensates. However, overcompensation(ratio of insulin to glucose) for a quicker spike is more dramatic according to studies, that of course I can't site right now because I sold my books back to the college book store and being able to site the place I learned this would be too easy.

Some carbs are "simple," and some are "complex." Simple carbs are simple for your body to break down = more glucose in the blood stream at once = more insulin. Complex carbs break down slower = lower blood glucose levels = less insulin.

04-18-2001, 10:12 AM
Don't forget about third party entities like fibre, which slow down the digestion process of simple carbs. ;)

04-18-2001, 10:20 AM
I did however retrieve a chart that I used in a research paper on the subject. It shows the difference in time that it takes 10g of simple carbs vs 10g of complex carbs to get into the blood stream. As you can see, at no point in time during the metabolization of complex carbs, is there a high concentration of blood glucose as compared to simple carbs. Do simple carbs result in MORE glucose? NO. Do they result in a higher concentration of glucose at any given time? YES.

04-18-2001, 11:06 AM
Originally posted by gino

Chicken Daddy - you just said you agreed with Anthony, then made a statement that disagreed with anthony. Stop confusing us. lol

haha, actually i said: "all do increase insulin release. Just some more than others."

Notice i didn't actually say that simple carbs cause a greater spike than complex ones. I just said that some cause more of a release than others. Which is true. I just wasn't clear with it. I'm a twat like that :D

Now darling, lets never fight like this again. :)

04-18-2001, 11:20 AM
Yeah. Maybe we should seek counseling. You know, lack of communication is the main reason so many relationships don't last...

the doc
04-18-2001, 01:45 PM
Gino, i think is important to establish that all complex carbs aren't created equal. barley for instance will give stable blood sugar profiles and give the effects you describe. However, maltodextrin, white rice, white bread, white pasta (all complex carbs) are readily turned into sugar and will give high insulin response. Hell i can even taste the sweetness developing in my mouth as i chew some of these substrates.

04-18-2001, 03:32 PM
The Glycemic Index (G.I.) is a numerical system of measuring how fast a carbohydrate triggers a rise in circulating blood sugar -- the higher the number, the greater the blood sugar response. So a low G.I. food will cause a small rise, while a high G.I. food will trigger a dramatic spike.

Maltodextrin (complex carb) 150
Fructose (simple carb) 32

For more info, see http://www.mendosa.com/gilists.htm

It's not black or white Gino. Complex doesn't necessarily equal slow and simple doesn't necessarily equal fast.

04-18-2001, 04:52 PM
Yes Gino, we should really try and make this work...

04-18-2001, 06:24 PM
I think this is how it works. The GI just measures the amount of time for the carb to hit the bloodstream. I DOES NOT measure the amount or spike of insulin that is released.
Are there high GI foods that spike insulin high yes, are there low, I would say yes. When an apple is eaten it may take a while to hit the bloodstream, hence the low GI, but when it does, bam. A good squirt of insulin is released relative to the size of the apple.

I MAY be wrong but you cannot tell me that if you ate sugar(low GI) for all your daily carbs vs oatmeal(medium, but higher than sugar) that you wouldn't have problems.

John Berardi over at tmag wrote an article that said something about GI does not measure insulin. I'll have to give it another read.

Damnit I don't know! I'm just staying away from simple sugars!

04-18-2001, 07:02 PM
the glyceamic index is measure of blood glucose levels and not insulin.
for the apple the glucose level will steadily rise and steadily fall, you will not get a quick squirt. while a high glyceamic food will quickly cause the glucose level to rise very quickly and fall very quickly.

04-18-2001, 08:28 PM
Yes. that's what I ment by a squart, steady rise, steady fall, not quick.

04-19-2001, 01:32 AM
Doc's first post on the matter was 100% correct.

04-19-2001, 03:38 AM
What happens when your blood glucose level increases?

Are any of you diabetic or familiar with diabetic research?

I'm going to quote Rick Mendosa again ... try to read it very carefully.

"The Glycemic Index (G.I.) is a numerical system of measuring how fast a carbohydrate triggers a rise in circulating blood sugar -- the higher the number, the greater the blood sugar response. So a low G.I. food will cause a small rise, while a high G.I. food will trigger a dramatic spike.

Before the development of the glycemic index beginning in 1981, scientists assumed that our bodies absorbed and digested simple sugars quickly, producing rapid increases in our blood sugar level. This was the basis of the advice to avoid sugar, a proscription recently relaxed by the American Diabetes Association and others.

Now we know that simple sugars don't make your blood sugar rise any more rapidly than some complex carbohydrates do. Of course, simple sugars are simply empty calories, and still should be minimized for that reason.

Many of the glycemic index results have been surprises. For example, baked potatoes have a glycemic index considerably higher than that of table sugar."

04-19-2001, 03:43 AM
I just thought about what I wrote, it's not right. I'm just going to eat my oats :)

04-19-2001, 03:54 AM
I just found the article on t-mag that talks about insulin.


Everyone has their own opinion, but it is a pretty good read.

04-19-2001, 04:10 AM
good post Anthony.

Bottom line ...... any excess Glycogen ... will be stored as fat if not used. Period.

the doc
04-19-2001, 06:29 AM
THis has been a good thread that started w/ a good question. Hopefully a lot of people will see it. I will bump it for a little while.

04-19-2001, 06:36 AM
And i thought it was a stupid question, LOL.

04-19-2001, 06:39 AM
Never forget that "Your the Man" ;)

04-19-2001, 06:42 AM
Damn straight :)

04-19-2001, 03:07 PM
Man, I am still confused.

1.High GI Carb = fast blood glucose spike
Low GI Carb = slow, level blood glucose increase

2. Simple sugar = in general a higher GI carb but not necessarily true (depends on other things like fibre, etc.)

3. Blood Glucose spike -> insulin spike?

4. Blood Glucose spike -> greater fat storage if unused?

5. Blood glucose spike -> blood glucose drop later on and therefore starvation response? (ie. similar effect to when you eat too infrequently)

I guess the last three are where the rubber hits the road :)


Podium Kreatin
04-19-2001, 05:33 PM
high gi usually spikes insulin highly
insulin nourishes fat as well as muscle, so insulin spikes could make u gain fat, not glycogen spikes.

07-10-2003, 01:29 PM
Great thread, and it was from back in 2001 :)

Just what i wanted, another question that comes to my mind is; to what effect does protein and fat reduce an insulin responce?

For example if i was to take a MRP consisting of 470cals 23g protein, 46 carbs (of which sugars 30) and 23.6 fat, what would the insulin repsonce be?

or would the fat and protein consumed negate a large insulin responce, brad, cd, the doc?

B-R ;)

07-10-2003, 01:47 PM
Christ almighty, i'd forgotten all about Gino and my love affair. Can't for the life of me remember what started it all off either.

Ron - combining all three macros will reduce the the rate glucose enters the blood stream so will theoretically cause a less, but more prolonged insulin secretion. Of that, that's judging off the GI, which doesn't always correspond with th insulin score.

But if you were to eat that amount of carbs alone (of maltodextrin probably if it's an MRP) then the rate of digestion would be quicker than compared to the entire MRP (depending on what is currently in your stomach and what time you ate it), and so i'd expect a lower, prolonged insulin response.

The actual insulin response for anybody after eating that is anyone's guess, but all that you really need to realise is that combining protein and fat with carbs in your meals will slow digestion compared to eating the carbs alone and so expect a lesser insulin response. I doubt you'll ever "negate" insulin totally if you're consuming carbohydrate of any kind. Even fibre has a small amount of digestible carbohydrate but certainly not enough to cause any significant shifts.

07-10-2003, 03:09 PM
cheers for the info Rob & lol @ the 'love affair' i wish i was around those days :)

I think negate was the wrong word, because insulin is a vital hormone in preventing the catabolism of muscle tissue if i recall, so you need so insulin responce, i was just wondering about the effects of other macros.

07-11-2003, 01:06 PM
Actually, anti-catabolism is a second class responsibility of insulin. It's first and foremost function is to control blood sugar (along with glucagon).

Just think, without insulin if you eat a large carbohydrate meal elevating your blood sugar - what would happen?

Your brain would proverbially drown in glucose since the GLUT1 of the blood brain barrier do not require glucose to allow glucose transport, you'd therefore go hyperglycaemic, and there's good potential you'd fall into a coma.

And there's the potential death issue. But insulin is anti-catabolic and that's all that matters.