If I had a nickel for every time a client told me that “sugar makes you fat” I’d probably be on my way to affording my very own candy shop. Anyone who hasn’t done their research on the components of sugar and human physiology would agree: If you want to lose weight, cut the sweet stuff out of your diet first and poof! The pounds will melt off.
But is it really that simple? In my years as a researcher and science student, I’ve come to learn that nothing is as black and powdery-white as it seems. I’ve said before that the health industry has an obsession with demonizing foods. Is it possible that sugar has been caught in the crossfire?
Let’s break it down and look at the claims regarding the sweet stuff.
First of all, we need to understand what sugar IS before we make any rash decisions.
Discussion topics in this post:
What IS sugar?
What happens when we EAT sugar?
Why Does Sugar make you fat (supposedly)?
Is Sugar addictive?
What about Blood Sugar?
Are some sugars worse than others?
What even IS sugar?
Sugar is simply a blanket name given to a group of typically-sweet carbohydrates (a biological molecule consisting of carbon, hydrogen, and oxygen), and it comes in many forms in nature (and the store). There are three main groups of sugars- MONOsaccharides, DIsaccharides, and POLYsaccharides. Sugars are categorized into these groups based on their chemical structure: Anyone who knows basic Latin has already figured out that MONO- means “one”, DI- means “two”, and POLY- means “many”.
MONOsaccharides cannot be broken down into a smaller molecule in the body. DIsaccharides are two joined monosaccharides and can therefore be split into two separate molecules in the body. POLYsaccharides are simply many monosaccharides bonded together to form a chain that can be split apart into numerous smaller molecules.
There are three main MONOsaccharides in the human diet:
- Glucose is the most important molecule to organisms (including humans). It Is the most widely-used carbohydrate in all living things, and functions as an energy source through three metabolic pathways. For humans, glucose is the KEY source of energy for ALL of our cells. When you talk about your “blood sugar” that’s glucose circulating in the blood. Glucose is imperative – it supplies almost all the energy for our brains to properly function. Therefore it influences all of our psychological processes. Studies have found that when glucose is low, processes like decision-making and self-control are impaired.
- Fructose is sweeter than glucose, commonly found in “natural” food sources like honey, fruits, flowers, and vegetables. It is absorbed directly into your blood from your intestines and is changed into a molecule that can be inserted into the same energy pathway as glucose.
- Galactose is a building block to lactose, commonly found in milk and its by-products. Like fructose, galactose is absorbed by the digestive system into the blood and converted to a molecule that can be inserted into the glucose-energy pathway for cellular energy.
*Before we move on, let’s reflect on our monosaccharides- notice that all three of them can be inserted into the SAME metabolic pathway in the body. Got it? We will revisit this later.
There are 2 main DIsaccharides in the human diet:
- Sucrose is composed of one molecule of glucose and one molecule
of fructose. It plays an important role in our diets; it is a common food additive, used as a sweetener, preservative, and thickening agent for other foods. It has a long history in our diets- dating back almost 2,000 years.
- Lactose is a combination of a glucose and a galactose molecule. This sugar is the main component of mammalian milk products like breast milk and the dairy we consume from other animals.
There are three common POLYsaccharides in the human diet:
- Glycogen is made up of a long chain of glucose, this is the MAIN form of glucose storage in humans. It is stored mainly in the liver and muscles, but has also been found in other tissues like the brain, kidneys, heart, and erythrocytes. Glycogen is our bodies’ primary energy source in the body, as it is broken down quickly into individual molecules of glucose for energy.
- Starch is composed of multiple glucose molecules. Plants tend to use starch as their glucose storage molecule. This is why we consider potatoes, other root vegetables, and breads “starchy” carbs.
- Cellulose is used as a structural material in plants. Humans cannot digest cellulose (it’s also called fiber) but many grass-eating animals (more specifically ruminants) contain bacteria in their gut to digest it. Most people don’t know that cellulose is also made up of glucose, but human digestive systems cannot break the structure apart and can therefore not access the energy those molecules of glucose could provide.
Some of you may be surprised. Starch? Fiber? They’re made up of glucose just like table sugar? Basically what I’m saying is that the carbohydrates we eat in our food are all glucose-based molecules. All of them. And going purely on true scientific definition, ALL carbohydrates are sugars. Not just that white stuff you keep hidden in the back of the pantry. That includes the carbohydrates in your raw, organic, gluten free, magical-properties-possessing quinoa energy balls.
*Since sugars are carbohydrates, they contain the same caloric values: 4 calories per gram (excluding cellulose or other fibres).
What happens when we eat sugar?
Every single living cells that makes up our bodies is in a state of ceaseless activity, depending on a constant series of impeccably-coordinated biochemical reactions. The carbohydrates we consume are a crucial aspect of what fundamentally drives these reactions.
So, let’s say we grab a handful of gummy bears or chow down on an apple as a snack. What happens to that sugar once it has been swallowed?
Sugars are broken down into their monosaccharide forms in the small intestine, where they are then absorbed into the blood stream. Remember, I stated above that all monosaccharides are eventually inserted into the same metabolic pathway for energy as glucose. For the sake of simplification, let’s just focus on glucose itself.
Once glucose is transported from our bloodstream into our cells, it undergoes a process called glycolysis. This cycle consists of ten (10!!) reactions that create ATP – our main energy source. Now, the rate of ATP synthesis in your cells directly parallels the intensity and amount of exercise you do. In other words, the more you exercise, the more energy your cells need to make (While fats can also synthesize ATP, it is too long of a process to be done during physical activity). It then makes logical sense that research shows a low-carb diet is associated with a decrease in performance and training volume thresholds in athletes.
So, glucose is essential for us to perform physical activity. And the easiest way to obtain glucose is from eating sugars. But then- Why does everyone say sugar makes you fat?
Now I’m sure that, while I’m sitting here telling you how essential it is to our bodies, the person beside you on the elliptical is raving about how “sugar is causing weight gain”, and that low-carb is the way to go, especially the Ketogenic diet that’s gaining ground as of late. So why does sugar have such a bad reputation?
To the public majority, sugar has been associated with increased rates of cancer, cardiovascular disease, type 2 diabetes, and [the big one] obesity.
So the logical explanation for this is, obviously, that sugar gives you cancer, heart disease, diabetes, and makes you fat, right? If we cut it out of our diets, we can essentially optimize our health and physique.
HOLD ON! Stop there, because what I’ve just provided to you is called correlational research data. This is simply the relationship two variables have with one another. This does not link any CAUSATION with sugar and ill health. Just because we find two different trends together (high sugar consumption and obesity) doesn’t mean we can immediately jump on the sugar-hate bandwagon and start burning down gingerbread houses with a low-carb vengeance.
High sugar consumption is considered a “marker” for an unhealthy lifestyle. Those who consume excessive levels of sugar tend to have other not-so-healthy habits too– like inactivity, lack of proper sleep, smoking, and over-eating unhealthy foods. Sounds like a recipe for cancer, type-2 diabetes, and obesity to me.
Another thing to understand is there is a difference between sugars and added sugars. When people demonize the sweet stuff it’s usually in regards to added sugars in foods, which provide “empty calories” to whatever you’re eating. What does that mean? In sugar’s case, it means the sweet stuff adds calories to foods but contributes no nutrients for optimizing health. Sugar has been shown to have very little affect on satiety, as well as low levels of micronutrients like vitamins and minerals. It is also very low-volume, meaning you can pack a lot of it into a small amount of food. Eating or drinking something that’s small, high in calories, and won’t help you feel full? I can’t imagine a better recipe for disaster.
Complex vs Simple Carbs
While it is easy to label SIMPLE carbs as “BAD” and COMPLEX carbs as “GOOD”, the actual distinction between them is random. It is merely a medical tradition, you could say. “complex carbs” simply have 3 or more sugars, whereas “simple carbs” only have one or two sugars.
So that begs the question, is it sugar itself that is the enemy, or is it simply the extra calories that tend to come with it?
Consider Gatorade: a common sports drink consumed by those perusing the world of any athletic endeavour. One bottle has 38g of carbohydrates, all coming from sugar.
The same goes for Cola: a single can serves up 39g of carbs in the form of added sugars. One or two gatorades or colas a day can add on almost 500 calories to your daily consumption! And do those drinks make you feel full? Heck no they don’t! 10 minutes after chugging a can of soda you’re ready for some real food, am I right?
So aside from sugar being easy to over-consume, what does the research say about the sweet stuff itself when we control for other variables like caloric consumption?
Let’s talk about two recent studies that controlled for overall caloric intake.
- A 2000 study that recruited 390 (!!) people over 6 MONTHS (yep, that’s right) found no significant difference in body composition between groups that consumed simple carbs (like fructose and lactose) versus those that consumed complex carbs (like oatmeal and rice). They measured body weight loss, fat loss, and blood lipid levels in all groups. Changes in blood lipid levels were also not different between the treatment groups. That study concluded that simple vs complex carbs did not produce any difference in body composition or blood lipids levels, although the diet itself (lower calories) had a signifiant impact on body composition of the candidates (It is important to note that in this study, calories, protein, and fiber were the same across diet groups).
- A 2001 study recruited 95 people to partake, one group consuming a low sugar diet (with 5% of total energy from sucrose) and a higher sugar diet (with 10% of total energy from sucrose). All diets put subjects 600kcal under their maintenance calories and all candidates received 33% of their energy from fat. After 8 weeks, the higher-sugar group actually lost MORE weight, although not enough to be statistically significant. The study concluded there was no justification for excluding added sugar in weight-reduction diets as long as overall calories were controlled.
- A 2006 study found that moderate carbohydrate/sugar diets AND ketogenic diets (severely low carb) were equally effective for weight loss in subjects once calories were controlled. In fact, the moderate-carb group suffered less inflammation, less energy loss, and less emotional strain than those on the keto diet. This particular study goes so far as to warn against low-carb or ketogenic methods of dieting.
So sugar doesn’t make us fat then? Well, that’s where science falls short. Unfortunately, research isn’t very good at telling us EXACTLY what’s going on. It does a much better job at pointing us in the right direction and eliminating variables or hypotheses we may have previously had. ALL studies have short-comings, and they must be taken into account. Most studies like this aen’t performed in controlled environments, and research relies on subjects telling the complete truth and following the plan 100% for the duration of the study. I don’t know about you, but if I was told to go on a diet and then set free, I don’t think I’d be very strict about following it unless there was a sizeable amount of compensation at the end of it all (in money or peanut butter, it really wouldn’t matter).
Is sugar addictive?
Here’s my favourite one. Ever heard the line pulled: “But sugar is more addictive than cocaine!” ? I have. Sadly, more than once.
Here’s where this belief came from. Some scientists decided to give rats 2 options: Water sweetened with sucrose OR water containing cocaine (a highly addictive compound). Surprise surprise, 94% of the rats chose the sweet water over the cocaine water. Maybe because it tastes better, or rats can perceive its relative safety or nutritional value over cocaine? Who knows, but the uncontrolled variables in studies like these are nearly endless. We apologize now for such flawed science – linking an association to direct causation, no less- coming out into the world. News stations and health gurus were like kids at a candy store, with sugar suddenly becoming “more addictive than cocaine”.
A 2016 systematic review (meaning it compiled all the present studies and research into one review) found “little evidence to support sugar addiction in humans” even when it comes to psychological stimulation, and argue against anyone prematurely incorporating the “science of sugar addiction” into published literature.
What about Blood Sugar?
We all know that sugar causes a major blood sugar spike, followed by the tell-tale crash a short while later. But based on research, this is actually a MYTH. Sugar (or sucrose in this case) has a glycemic index (GI) of ~65 (+/- 4). That falls under “medium” and not “high” when it comes to effect on our blood sugar. For reference, boiled brown rice is 68 (+/- 4), and the higher the number, the more extreme of an effect it has on blood sugar.
Are some types of sugar worse for us than others?
Well, not really. Turns out there isn’t much evidence to support different types of sugars having different effects on blood sugar. In fact, experimental evidence has indicated that the source of sugars in foods has no affect on the rate of absorption of the sugars. the biggest factor in rate of blood sugar rise was the properties of the foods eaten WITH the sugars. Therefore, worry less about what type of sugar you’re consuming and more about the whole foods you’re going to pair with it- that are high in fiber, protein, and fats, right? [so not the entire bag of M&M’s on its own….]
The Bottom Line
Sugar isn’t bad for you, but it’s not necessarily good for you either. It’s not nutritious, contains little micronutrient content, no fiber or volume, and isn’t satiating at all. But it also has no direct causation to chronic disease, cardiovascular health, or weight gain. At the end of the day, an apple or a snickers bar is going to be broken down into the same metabolic pathway as glucose for energy.
There is little concrete evidence to prove that a moderate amount of sugar, when combined with adequate levels of protein, fats, fiber, and micronutrients as part of a healthy lifestyle is BAD or UNHEALTHY. Sugar is no more fattening than any other carbohydrate or food you consume, and if your diet consists of sugar in moderation, you’re not harming your body, organs, or physique goals in any way.
Don’t avoid fruit, dairy, or added sugars solely because you think it’s going to kill you. Fruit consumption as a main staple in human evolution dates back more then 6 million years. Many cultures all over the world, even today, rely on diets high in simple carbohydrates, like the Hazda from Tanzania that rely mainly on honey for their nutrition intake.
Sugar content of foods should NOT be your sole determinant of health – rather than just focusing on a single energy source, you should consider balancing your entire diet as opposed to cutting out only one nutrient in particular.
Hopefully you can now make more informed decisions about what sugar is and how it affects our bodies. And next time that zealot on the elliptical wants to sell you more KETO-drink powder because “sugar causes fat gain” you can drop some hard knowledge right on his low-carb head.
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©2018 EVLV fit
EVLV fit is not a physician or registered dietician. This website, the information disclosed on it and all of its contents are not intended to diagnose, treat, or prevent any medical health problems. It should not be used in replace of advise from a medical physician. Always consult your doctor, physician, or qualified medical health professional for health matters.