The Truth About Sugar
Sugar. A nutrient cynically engineered by the devil himself with one purpose; to destroy the race of mankind, one chocolate chip cookie at a time.
Without a doubt, we can all agree that sugar is bad for you, right?
In this article we’ll see what the science really says.
Talk to a trainer, a nutritionist, or your mom, and each one will give you the same clean-cut piece of advice when it comes to your diet; cut out sugar.
In most people’s minds, sugar is not only bad for your fattening and bad for your physique but its flat out detrimental to your health.
The claims against sugar go something like this; it’s pro-inflammatory, it spikes insulin, leads to fat gain, and promotes a whole host of negative health outcomes, including obesity, diabetes, cardiovascular disease, stroke, and cancer. Claims such as these have played a large role in solidifying our negative view of sugar over the last 50 years.
But where did these claims come from? Are they scientifically valid or are they just hearsay?
According to the National Institutes of Health, more than two-thirds of adults in the United States are considered overweight and more than one-third are classified as obese. The rates of type II diabetes, heart disease, high blood pressure, non-alcoholic fatty liver disease, stroke, metabolic syndrome, and cancer are higher than ever.
Obesity rates and the prevalence of their associated diseased states have been on the rise since the late 1940s. Coincidently, so has our average consumption of sugar, mirroring that of the obesity epidemic and highlighting sugar as a prime suspect in our declining health and increasing waistline.
However, as any good researcher will tell you, “Correlation does not equal causation”.
A classic example illustrating this concept is the association between ice cream sales and murder rates. Generally speaking, as ice cream sales increase, so do the number murders. However, despite the fact that these two variables are positively correlated, it doesn’t mean that ice cream is actually “causing” murders.
A bowl of mint chocolate chip doesn’t turn you into a psycho killer. Perhaps there is a third unseen variable, such as the season or outdoor temperature, that is having an effect on both ice cream sales and murder rates simultaneously. Or perhaps the association is just occurring by random chance.
It’s very important, particularly when interpreting observational research, not to infer causation from correlation. While correlations are great for identifying possible causal relationships, they do not demonstrate that one thing is the direct cause of another. There is a long list of variables that are positively correlated with the obesity epidemic, including bottled water consumption. However, I don’t hear anyone arguing that bottled water causes fat gain.
When it comes to sugar, if you consider the more recent observational data from the USDA, it demonstrates that sugar consumption has actually decreased in the United States over the last 15 years, however, the incidence of obesity has continued to rise. This is where the correlational data really starts to break down.
No matter what the observational data looks like, we can’t come to any definitive conclusions about sugar based on correlations alone.
Sugar is definitely associated with fat gain and poor health; however, we have to ask ourselves,
Is sugar itself the cause of weight gain or could it be the calories that come along with it?
We know that weight change is ultimately controlled by energy balance, the relationship between the number of calories that are taken into the body via food and drink versus the number of calories that are used up within the body for basic energy requirements.
When energy consumption, “calories in”, exceeds energy expenditure, “calories out”, the result is weight gain. This is a bit of a simplified model, however, it’s factually based on the fundamental laws of physics and can’t be refuted.
Foods higher in sugar tend to be much more calorically dense, lower in their nutritional value, and aren’t very filling. Sugar essentially introduces “empty” calories into the diet that possess little nutritional benefit.
However, the biggest issue concerning sugar is that it tastes good, making foods that contain it very easy to overeat.
Additionally, most junk foods aren’t comprised of sugar alone, they contain a combination of fat, sugar, and often times sodium, making them very calorie dense, extra tasty, and very rewarding to the brain to consume. Foods like this are referred to as being hyperpalatable.
Hyperpalatable foods have the ability to override our brain’s normal energy regulating systems, causing us to consume excess calories that our body doesn't need. This is why dessert still sounds good to us after dinner, even when our stomach is stuffed. No one ever smashes an extra serving of broccoli or chicken after they’re already full. But cake on the other hand is a different story.
The truth is, people who consume high sugar diets also tend to consume more calories. Based on the characteristics of sugar containing foods, it’s easy to see how a high sugar diet could facilitate an excess intake of calories and promote weight gain.
Additionally, those who consume higher intakes of sugar also tend to be less physically active, are more likely to be smokers, and often possess other poor eating habits, such as consuming a very minimal amounts of fruits, vegetables, and whole foods. Again, this is just correlational, however, it helps to demonstrate that there may be another cause for our health crisis. Sugar isn’t off the hook yet.
If excess calories are the culprit, and not sugar itself, then sugar intakes shouldn’t make a difference in body composition or health if calorie consumption is controlled for.
Lucky for us, we have plenty of research examining just that.
A 6-week calorie-controlled weight loss study compared a high-sugar diet to a low-sugar diet and found no significant difference in weight loss, bodyfat percentage, or biomarkers of health between the two different diet conditions (Surwitt et al, 1997).
This study in particular is note-worthy because it compared two drastically different intakes of sugar, the high-intake group consuming around 118g per day and the low-intake group consuming about 10g per day. Both groups experienced similar decreases in weight, blood pressure, bodyfat, and plasma lipids. There was a slight advantage in favor of the the low-sugar group as far as blood cholesterol and blood lipids were concerned, however, the effect was very small and could have been due chance or to alternative factors such as fiber intake.
There are a multitude of studies comparing low-sugar diets to high-sugar diets. In almost all cases, when calories are controlled, there is little to no differences in body composition or health markers. Especially when other variables such as protein and fiber intake are controlled for as well.
A huge 2013 systemic review and meta-analysis on dietary sugar and bodyweight (Te Morenga, Mallard, and Mann, 2013) looked at sixty-eight different studies and concluded;
When calorie intake is controlled for, sugar is not associated with weight change or body fatness.
They also stated that these findings strongly suggest;
Energy imbalance is the major determinant of the potential for dietary sugar to influence measures of body fat.
As you can see, the data supporting the notion that sugar itself is inherently fattening or detrimental to health is very weak.
It appears that sugar is not necessarily the bad guy that many of us have made it out to be. Rather, we should point the finger at an overall excessive intake of calories, which seems to be the real cause for our declining health and expanding waistline.
Even further, we can more appropriately point the finger at hyperpalable foods that make it extremely had to regulate energy intake and maintain healthy bodyweight.
So, what your saying is that sugar is good, right!?
I wouldn’t say that sugar is good. However, I wouldn’t say that it's bad either. The scientific truth concerning sugar doesn't really provide a 'good or bad' 'black or white' answer. It lies somewhere between these two extremes.
Like many things in health and nutrition, its context dependent.
Sugar doesn’t need to be avoided like the black plague, but I wouldn’t consume it with reckless abandon either. For the most part, its nutritionally void, its easy to eat too much of, and isn’t good at managing hunger.
Your first dietary priority is making sure that your calorie intake is in order. Any food or macronutrient, sugar or not, can make you fat if consumed in excess.
Once you know your calorie intake is in order and your energy balance is in line, then you can focus more specifically on your sugar intake.
The World Health Organization recommends that added sugars should make up no more than 10% of your calories per day, which is a prudent guideline to go off.
For the average person this equates to about 50g of sugar a day.
Most of the negative effects of sugar are due in large part to one type of sugar in particular, fructose, which is combined with glucose to make what we common think of as table sugar or sucrose.
Another health recommendation is to consume no more than 50g of fructose per day, which equates to about 100g of sucrose or table sugar.
If your diet consists of whole foods most of the time, your calorie intake is in check, and your consuming no more than 100g of sugar a day, then you’re going to be just fine.
Surwit, R. S., Feinglos, M. N., McCaskill, C. C., Clay, S. L., Babyak, M. A., Brownlow, B. S., ... & Lin, P. H. (1997). Metabolic and behavioral effects of a high-sucrose diet during weight loss. The American Journal of Clinical Nutrition, 65(4), 908-915
Te Morenga, L., Mallard, S., & Mann, J. (2013). Dietary sugars and body weight: systematic review and meta-analyses of randomised controlled trials and cohort studies. Bmj, 346, e7492.