Why Poptarts are Not A Good Post Workout Meal: The Truth About Fructose
There are no “evil” nutrients, and there are no “good” foods or “bad” foods. Nevertheless, there are foods that should be treated differently than others. This is particularly true of fructose, a sugar that is found in fruit naturally and is added to many processed foods in the form of high fructose corn syrup.
There is currently an academic battle being waged over fructose between scientists who say that overeating fructose is dangerous, and other scientists who say that fructose is no different from any other carbohydrate. The former generally argue that fructose has a particular impact on fat metabolism, while the latter argue that overall consumption of calories is the issue, not fructose consumption.
So what is health nut or a muscle head to do when it comes to fructose?
This blog will take you through the research in a manner that you can understand and will make some general recommendations for you in your treatment of fructose in your own diet.
The Big Problem for Athletes, Bodybuilders and Everyone Else
In a recent peer reviewed journal article, researchers presented a study in which they examined fructose’s effect on established lipid targets for cardiovascular disease. They found no effect from fructose on cholesterol (HDL, LDL) or triglycerides when fructose was exchanged for other carbohydrates. They did find some effect of fructose on lipid markers when fructose was added to the caloric load. The overall recommendation from this study was that people should focus on lowering calories rather than focusing on fructose as a “bad” food. This is contrary to other studies that found that fructose did have a negative impact on health. ,
Here’s the thing, this entire study is paralyzed by a logical fallacy. Namely, this study assumes that total low density lipoprotein (LDL is a good measure of risk for heart disease. As we learned from my blog on saturated fat, there is small densely packed LDL particles and larger fluffy LDL particles. , This is an important distinction because individuals with smaller and more densely packed LDL particles are three times more likely to die from heart disease than those with a greater number of larger LDL particles.  Because of this fact, total cholesterol and overall LDL are poor indicators of whether or not someone will actually get heart disease, and the research presented in the pro-fructose article does not accurately measure or predict whether or not fructose has an impact on heart disease or health.
Now, keeping in mind that the pro-fructose research was partially funded by the Coca Cola Company, lets delve into the facts about fructose and its impact on health and athletics.
Glucose and fructose are both sugars, but fructose is much harder to digest. As such, little to no fructose ever makes it to become muscle glycogen.  Rather, fructose goes directly to the liver, which has it’s own storage capacity of around 400 calories of glycogen (or around 100 grams). We can extrapolate two main facts from this knowledge.
- Fructose is not good recovery aid. Given that fructose does not store as muscle glycogen, consuming anything made of fructose or high fructose corn syrup for recovery purposes is really not a good idea. While fruit is not bad, you definitely should not use it for this purpose, and don’t use your workout recovery as an excuse to drink sugary soft drinks, eat pop tarts, or to consume any food with high fructose corn syrup. It’s a free world, and you can eat what you want, but posting an instagram picture of yourself munching on a Poptart post workout “for recovery” is not something you should be bragging about.
- Too much fructose could easily inhibit fat loss because, once the 400 calorie capacity of the liver is reached, any additional fructose consumed will be converted into fat. This is especially true if your stores are already full from eating other sources of carbohydrate.
Does this mean that fruit is bad?
No, it definitely doesn’t mean that fruit is bad. Fruit has far less calories from fructose than do soft drinks or toaster pastries. Just don’t over eat it and limit your consumption to one or two pieces of fruit a day, especially if you are eating other sources of carbohydrate in high volume. My advice is to focus on darker skinned fruits like blueberries, as these have higher nutrient density for the calories and you can get more benefit out of what you do eat.
Part of the quest to be more fit is in educating yourself beyond the headlines the media put in front of your face. This study made a lot of headlines, but it is flawed, and if you follow it’s logic in thinking that consuming high levels of fructose will have no impact on your health, then your fitness and health goals could be stalled.
As always, if you have any questions or are interested in consulting with me on nutrition or training, email me at [email protected]
 Chiavorili et al. 2015. Effect of fructose on established lipid targets: a systematic review and meta-analysis of controlled feeding trials. Journal of the American Heart Association. Doi:10.1161, available at http://jaha.ahajournals.org/content/4/9/e001700.full.pdf+html
 Bray, GA. 2013. Energy and fructose from beverages sweetened with sugar or high-fructose corn syrup pose a health risk for some people. Advanced Nutrition. 4(2), 220-5
 DiNicolantonio et al. 2015. Added fructose: a principal driver of type 2 diabetes mellitus and its consequences. Mayo Clin Proc 90(3), 372-81.
 Dreon et al.1998. Change in dietary saturated fat intake is correlated with change in masss of large low-density-lipoprotein particles in men. The American Society for Clinical Nutrition. Volume 69, p. 744.
 Siri-Tarino et al. 2010. Saturated Fat, Carbohydrate, and Cardiovascular Disease. American Journal of Clinical Nutrition. 91(3) 502-509.
 Austin et al. 1988. Low-Density Lipoprotein Subclass Patterns and Risk of Myocardial Infarction. Journal of the American Medical Association. 260(13), 1917-1921.
 Conlee et al. 1987. Effects of glucose or fructose feeding on glycogen repletion in muscle and liver after exercise or fasting. Ann Nutr Metab. 31(2), 126-32.