Insulin And HFCS

Unruly insulin levels can royally screw up your physique. Specific foods affect insulin levels. However, what may be more important is knowing what specific ingredients in foods mess with insulin. You can lift all day until you are blue in the head, but eating specific foods and food ingredients could be holding you back from resembling the chiseled Statue of David.

First A Little Background

Insulin is THE most anabolic hormone in the body. Insulin’s anabolic properties make it rather important when thinking about packing on muscle. However, too much insulin could cause you to resemble Professor Klump from The Nutty Professor. Here’s how it works.

Insulin secretion occurs via the β-cells in the pancreas with the consumption and digestion of food; particularly in response to carbohydrate-rich foods. Over stimulation of the β-cells, characterized by diets consistently high in simple sugars (e.g., a “soda and Twinkie” type diet) may lead to insulin resistance overtime (probably because that kind of diet is usually accompanied by weight gain). Basically, when you consume high sugar foods, blood glucose is chronically elevated and insulin is continually released to control blood glucose levels (not allowing them to go too high).

Chronically elevated insulin levels decreases the bodies ability to burn fat, increases triglycerides, decreases HDL levels (the good cholesterol) and causes excessive peroxidation (the stuff we pay lots of money to avoid by buying eating lots of fruits and vegetables and antioxidant supplements)!

Therefore, dietary control and exercise are imperative since both help regulate glucose. In addition to the umbrella classification of high sugar foods, there are two specific ingredients that need to be considered: fructose and more specifically high fructose corn syrup (HFCS). Both are found in a wide variety of foods, many of which may surprise you.

Fructose And Insulin

Here’s the scoop. Fructose is a monosaccharide (one sugar) that is often referred to as “fruit sugar” because it is the primary carbohydrate in most fruits. Fructose is also the primary sugar in honey and makes up half the carbohydrate in sucrose (table sugar). The interesting thing about fructose is that it does not stimulate insulin secretion and does not require insulin to be transported into cells, like other carbohydrates.

After all the talk about the importance of controlling insulin levels, it appears as though a lack of insulin secretion from fructose consumption may be a good thing. However, insulin also controls the fate of another hormone, leptin, so as you’ll see, its release is necessary.

Leptin tells your body to stop eating when it’s full. Essentially, leptin signals the brain to stop sending hunger signals because the “tank is full”. Since fructose doesn’t stimulate insulin, there will be no subsequent increase in leptin levels, and no feeling of satiety (i.e., you’ll keep eating and eating).

Is Fructose Making YOU Fat?

Fructose requires a different pathway for metabolism than other carbohydrates because it basically skips glycolysis (normal carbohydrate metabolism). Because of this, fructose serves as an unregulated source of something called acetyl-CoA, the starting material for fatty-acid synthesis. This, coupled with unstimulated leptin levels is setting you up for a big, fat disaster! It’s like opening the flood gates of fat deposition.

Don’t over interpret this; fructose should not be eliminated from the diet. This is more of a “heads up” since most readers of this site share similar health and fitness goals. Remember that fructose is the primary sugar found in fruits. Fruits provide a whole slew of nutrients that can’t otherwise be obtained from the diet so don’t toss them in the trash too fast. A little fructose, like that found in fruit, is OK. It’s when high levels of fructose are consumed, which is common these days because of the inclusion of sucrose and, even more so, HFCS into virtually all commercial foods.

High Fructose Corn Syrup

HFCS was brought to the market in the 1970’s by food companies looking to save money during production and, therefore, make more money from the consumer. HFCS hides itself in a variety of common foods such as ketchup, seasonings, barbeque sauce, soda, juices, cereals, pasta sauce, fruit-flavored yogurt and even some meal replacements powders, to name but a few. HFCS is popular among food companies because it is much sweeter than any natural sugar available, much cheaper, and easy to transport because it is a liquid.

While it may seem that this is just my over zealous mind taking things to extreme, read on; there are several animal studies to support my theories that body weight and adiposity both increase while consuming a high fructose diet (9,10,11). The data on humans is a bit more difficult to come across, but there are a few studies. For example, one study demonstrated that individuals consuming 28% of total energy from sucrose (remember, ½ the carbohydrate in sucrose is fructose) vs. artificial sweetener had a higher energy intake, body weight, and fat mass after a short 10-weeks (12).

This doesn’t sound like rocket science; greater energy intake equals greater weight gain. There were some interesting findings though. There was an increase of a little more than 400 kcals in the sucrose group, which should result in an approximate weight gain of 3.1 kg if all other factors are held constant. However, there was only about half that weight gain in this group. Therefore, the authors estimate that 48% of the excess energy intake from sucrose was used for other energy demanding body processes, such as lipogenesis (the creation of fat).

In addition, even though all subjects were told they were being given artificially sweetened products, most of those in the sucrose group guessed the true content of their beverages. Even though subjects knew they were consuming more calories from drinks, they didn’t compensate by eating less calories from other foods. Again, the authors suggest this could be a mechanism due to lack of control over eating behavior (remember the lack of insulin secretion and subsequent leptin production from fructose consumption talked about earlier).

Similarly another study demonstrated those consuming HFCS sweetened soda vs. artificially sweetened soda did not reduce participants total energy intake to compensate for the extra energy consumed as HFCS. These data, like above, suggest that the consumption of HFCS (from soda in this case) does not provide the body with a sense of fullness causing an increase in excess energy, hence, weight gain. I will say it again; fructose does not stimulate insulin or leptin, causing an increase in total energy intake because the “shut off switch (leptin)” is not registering that there is food in the body.

To make matters even worse, fructose consumption is even tied specifically to insulin resistance in rodents (suggesting it may have the same affect on humans too)(13,14) and increased triglyceride secretion (15).

So What Does This All Mean?

Let me sum up this whole article in one sentence: avoid HFCS like the plague! Go through your entire refrigerator, freezer and cabinets and read the ingredient labels with the same attention to detail you would use when going on a first date. If HFCS is high up on the list of ingredients (meaning there is a relatively large amount in the particular food) toss it in the garbage. Soda is one of the biggest culprits. It’s a great deal for the soda companies (e.g., use less of an even cheaper sugar for a sweeter product), but a heck of a deal for your body (e.g., get fat). Now of course HFCS alone cannot make you fat; for example soda made with “natural sugar” is still soda. However, coupled with an increased caloric intake (eating too much) and decrease energy output (not being active enough), you’re setting yourself up for a recipe for unhealthy disaster.

The easiest trick to avoid this (and many other “useless” ingredients) is to primarily shop around the perimeter of the store. Think about it: produce is on one side, seafood, red meat, poultry on another, and dairy products, eggs, bread on the third. HFCS infests commercially available products; the more these can be avoided, the better off you’ll be, both health and physique-wise. Try to buy foods in the most “natural” state possible; the less processing the manufacturers do, the better off you’ll be.

References:

1. JAMA, 286(10), 1195-1200, 2001
2. MSSE, 35(3), 449-455, 2003
3. Curr Opin Clin Nutr Metab Care, May;6(3):301-6, 2003
4. J Strength Cond Res, Feb;17(1):12-9, 2003
5. J Appl Physiol. Oct;93(4):1337-44, 2002
6. Can J Appl Physiol. 26 Suppl:S236-45, 2001
7. AJCN, 68, 794-801, 1998
8. AJCN, 74, 426-234, 2001
9. J Nutr, 112, 1546-1554, 1982
10. Br J Nutr, 70, 199-209, 1993
11. J Lab Clin Med, 128, 208-213, 1996
12. AJCN, 76, 721-729, 2002
13. J Nutr, 107, 147-155, 1977
14. Metabolism, 29, 970-973, 1980
15. AJCN, 49, 1155-1163, 1989

Dr. Chris Mohr RD, PhD is a health nutrition consultant to a number of media outlets and corporations including Discovery Health Channel, Clif Bar, Waterfront Media, and Fit Fuel. He has authored and co-authored several textbooks and textbook chapters, including consulting with LL Cool J on "LL Cool J's Platinum Workout" (Rodale Press, 2006). He is also co-creator of Meal Plans 101 nutrition software.