You eat sugar, your insulin spikes, you get fat, end of story. That’s how the story goes for people who are trying to sell you their products. But, because you are reading this, you must already know that the likes of food babe and “Dr.” Mercola are full of crap. So what really happens when you eat sugar? Well let’s take a look at what the science says and dispel some myths and ease the fear caused by those only looking to line their wallets.
Low Carb Diets
I’ll start by saying low carb diets work (1
). They work because they force you to eat fewer calories than you use throughout the day. The same way that any weight loss program works. But it’s not
due to some magical insulin pixie
. When you cut out a ton of calories, you are going to lose weight. It may seem obvious, but too many people mix up the message. A big part of why cutting carbs lowers your weight is due to water. Switching to a low carb diet will cause an initial sharp increase in total weight loss, but this is due to the drop in water weight that accompanies carb restriction (2). Of course this means that as soon as you start eating carbs again, you will regain the weight rapidly. Finally, ma
ny are successful on a low carb diet
because it automatically increases protein, which helps to curb appetite (3
). They also typically eliminate all junk foods, which is where our excess calories come from. Bottom line
, if it works,
I have written about this twice before (Part 1, Part 2), but the more internet garbage I read, the more I want to write about it. Here’s a good way think about insulin’s roll in weight gain “Insulin is like workers in a warehouse.
Calories are the boxes that the workers have to stack on shelves. If there’s lots of workers (high levels of insulin) and lots of boxes (a calorie surplus) then the boxes are packed quickly, and you get a build up of calories, i.e. fat gain. If, however, you’re in a calorie deficit, there are no boxes for the workers to store, so no matter how much insulin is present, there’s nothing to be stacked, and no fat mass to be added.” In other words, the only time carbs actually contribute to fat gain is in the context of a calorie surplus. It is also important to note that insulin sensitivity issues are most likely a result of obesity than it is a cause (4). Bottom line, it’s not the insulin.
Fructose & High Fructose Corn Syrup
For some crazy reason, there are people on the internet who are ranting on about how bad fruit is for you because it has f
ructose in it. In short, fruit is good for you for many reasons, and fructose is not bad. Moderate levels
of fructose consumption do not adversely effect body weight or blood chemistry. However, obscenely high levels of intake (>150 grams per day) may have undesirable health effects (5
). High fructose corn syrup (HFCS) has been blamed for the rise in obesity over the years. But the reality is that HFCS is the same as any other sugar
and has nothing to do with the rise in obesity (6
). Bottom line
, HFCS and fructose are sugar and nothing more. Keep your consumption in check and you will be fine.
Not so long ago, I can remember news outlets around the US saying that sugar is as addictive as narcotics. The thought was that sugars would impact the pleasure center of your brain as well as energy-regulating hormones including insulin, leptin, and ghrelin. This issue was popular because it would mean that our addiction would lead us to eat more sugar, which would make us eat more calories, and therefore make us fat. These stories got lots of views and clicks, so the media kept ‘em comin‘ for a while. The problem is that the stories were based on terrible studies. In reality, the “addiction” seen in animals (and possibly in humans) is due to intermittent access to sweet tasting or highly palatable foods, not the neurochemical effects of sugar (7
). Bottom line
, no one has ever needed to do a line of sugar because they got the shakes.
Inflammation, Diabetes, Heart Health & More
People from around the world, throughout history and today, have lived long, obesity-free and disease-free, lives while consuming carbs as much as 70% of their diets (8,9). If carbs themselves are fattening, these populations would not have had lean bodies and good health overall, regardless of how active they were. I’ve also heard talk around the gym lately that carbs, sugar in particular, cause inflammation and are therefore bad. Don’t get me wrong, chronic low grade inflammation is a real thing, and it is bad, but it’s not caused by fructose, high-fructose corn syrup, or glucose in normal-weight to obese adults. Not even when consumed in high amounts (10
). There’s also little support for a relationship between sugar consumption and diabetes, increases in blood pressure, non-alcoholic fatty liver disease, or cardiovascular disease (11
). Bottom line
, there’s no link between sugar consumption at normal levels within the human diet and various adverse metabolic and health-related effects.
Night Time Carbs
You will never guess what I’m about to say. Carbs at night
… are not bad! They can help you sleep, help fuel training performance
the next day, and carbs at night will have absolutely no negative effect on fat loss (12
). Consuming food at night has no effect on overall metabolism either. Bottom line
, be happy with your meals and don’t sweat that night time snack.
Low carb diets are good and bad. As mentioned before, going low carb or ketogenic means your diet is higher in protein, which helps to curb appetite and eliminates junk foods, which is where our excess calories come from. But in the long term, it means you have to sacrifice a lot. You will have a harder time going out and eating with friends, preparing meals will become far less convenient (especially for sandwich lovers like myself). You might feel worse, and have lower energy and overall mood. If anything, it will make it harder to lose fat in the long run due to a (s
lightly) lowered metabolism (13
). Some may say “if it works,
it works” but is it really worth the sacrifice? That’s up to you. The bottom line
however, is that carbs don’t make you fat. So the next time someone says that sugar is making the world fat, tell them “it’s because of junk food as a whole – the total calories – and not just the carbs.”
1. Westman, E. C., Yancy, J., William S, Mavropoulos, J. C., Marquart, M., & McDuffie, J. R. (2008). The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutrition & Metabolism, 5(1), 36-36. doi:10.1186/1743-7075-5-36
2. Kreitzman, S. N., Coxon, A. Y., & Szaz, K. F. (1992). Glycogen storage: Illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition. The American Journal of Clinical Nutrition, 56(1 Suppl), 292S.
3. Westerterp-Plantenga, M. S., Lemmens, S. G., & Westerterp, K. R. (2012). Dietary protein – its role in satiety, energetics, weight loss and health. The British Journal of Nutrition, 108 Suppl 2(S2), S105. doi:10.1017/S0007114512002589
4. Kahn, S. E., Prigeon, R. L., McCulloch, D. K., Boyko, E. J., Bergman, R. N., Schwartz, M. W.. . Palmer, J. P. (1993). Quantification of the relationship between insulin sensitivity and beta-cell function in human subjects. evidence for a hyperbolic function. Diabetes, 42(11), 1663.
5. Madero, M., Arriaga, J. C., Jalal, D., Rivard, C., McFann, K., Pérez-Méndez, O.. . Lozada, L. S. (2011). The effect of two energy-restricted diets, a low-fructose diet versus a moderate natural fructose diet, on weight loss and metabolic syndrome parameters: A randomized controlled trial. Metabolism: Clinical and Experimental, 60(11), 1551-1559. doi:10.1016/j.metabol.2011.04.001
6. White, J. S. (2008). Straight talk about high-fructose corn syrup: What it is and what it ain’t. United States: American Society for Clinical Nutrition, Inc. doi:10.3945/ajcn.2008.25825B
7. Westwater, M. L., Fletcher, P. C., & Ziauddeen, H. (2016). Sugar addiction: The state of the science. European Journal of Nutrition, doi:10.1007/s00394-016-1229-6
8. Lindeberg, S., Eliasson, M., Lindahl, B., & Ahrén, B. (1999). Low serum insulin in traditional pacific islanders—The kitava study. Metabolism, 48(10), 1216-1219. doi:10.1016/S0026-0495(99)90258-5
9. Zhou, B. F., Stamler, J., Dennis, B., Moag-Stahlberg, A., Okuda, N., Robertson, C.. . INTERMAP Research Group. (2003). Nutrient intakes of middle-aged men and women in china, japan, united kingdom, and united states in the late 1990s: The INTERMAP study. Journal of Human Hypertension, 17(9), 623-630. doi:10.1038/sj.jhh.1001605
10. Kuzma JN et al. (2016).No differential effect of beverages sweetened with fructose, high-fructose corn syrup, or glucose on systemic or adipose tissue inflammation in normal-weight to obese adults: a randomized controlled trial. Am J Clin Nutr.
11. Rippe, J. M., & Angelopoulos, T. J. (2016). Sugars, obesity, and cardiovascular disease: Results from recent randomized control trials. European Journal of Nutrition, doi:10.1007/s00394-016-1257-2
12. Afaghi, A., O’Connor, H., & Chow, C. M. (2007). High-glycemic-index carbohydrate meals shorten sleep onset 1,2,3. The American Journal of Clinical Nutrition, 85(2), 426.
13. Johnston, C. S., Tjonn, S. L., Swan, P. D., White, A., Hutchins, H., & Sears, B. (2006). Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. The American Journal of Clinical Nutrition, 83(5), 1055.