When I first got into fitness, I didn’t eat any sugar.
I would scour food labels, making sure there was absolutely no sugar in whatever food I was about to eat.
Birthdays, holidays, and parties were all the same for me. I would politely refuse whatever cake or treats everyone else was eating.
People would say things like “Oh, I wish I could be like you!” or “That’s how you stay so thin, you don’t eat any junk food!”
The truth was I was afraid of sugar.
I didn’t want sugar to ruin my progress. I thought any sugar I ate would immediately turn into fat.
I didn’t really know anything about sugar, or how fat is gained and lost. I would hear other fitness people talking about how bad sugar was, and how it needed to be avoided at all costs.
Sugar will make you fat!
Sugar is a toxin!
Sugar is more addictive than cocaine!
What’s the real truth? Is there any merit to these claims? Is sugar really that bad for you?
In this article, you’ll learn whether or not sugar is actually bad for you. You’ll learn whether you can enjoy it in moderation or you should avoid it like the plague.
Let’s jump in.
What is sugar?
When you think of sugar, you probably think of the sweet stuff in candy, cookies, brownies and other treats.
And then there’s sugar in honey, maple syrup, and agave.. but those are all natural sugars so they are supposed to be healthier, right?
You probably also know that fruit has sugar in it.. but that’s good sugar.. or is it the same?
When talking about sugar, things can get confusing because sugar can mean added sugar in sweets, and natural sugar in fruits and starches.
To further confuse things, in biology sugars are a form of simple carbohydrate. They are considered simple because of their structure.
So, sugar is made up of smaller sugars.
Let’s break them down..
Simple carbohydrates
There are two types of simple carbohydrates. They are called saccharides, which comes from the greek word for sugar.
The simplest form of sugar is called a monosaccharide. A monosaccharide is made from one sugar molecule. The three monosaccharides we consume are fructose, glucose and galactose.
Glucose is our body’s main source of energy. Many of the carbohydrates we eat are made of glucose, and our bodies can turn other simple sugars into glucose to use as energy.
Fructose is found naturally in fruits and vegetables, as well in products that contain high fructose corn syrup.
Galactose is found in dairy products.
Disaccharides are made from two monosaccharides combined together. The three common disaccharides we consume are sucrose, lactose, and maltose.
Sucrose is a combination of glucose and fructose. Sucrose can be found naturally in fruits and vegetables or it can be produced from sugar cane or sugar beets. This is usually the sweet stuff in cookies, cakes, brownies and candy. It’s the most common form of sugar.
Lactose is a combination of galactose and glucose. Some people lack the enzyme to break down lactose, which makes them lactose intolerant.
Maltose is formed by breaking down starches like wheat, barley and rye. It’s found in beer and malt liquor.
Complex carbohydrates
Foods like potatoes, breads, pasta, oats and beans are made up of long chains of sugar molecules called polysaccharides.
Polysaccharides can be up to thousands of sugar molecules linked together in complex patterns. Two common examples of polysaccharides are starches and cellulose.
Starches are long chains of glucose and are found in foods like potatoes, rice, pasta, breads and cereals.
Cellulose is a type of fiber found in leafy green vegetables and whole grains. It’s not digestible and helps add bulk to your stool.
What happens to sugars in our bodies?
Whether you eat an apple, a bowl of oatmeal, or a piece of cheesecake, our bodies break down carbohydrates into their simplest form of sugars.
All digestible carbohydrates become either glucose, galactose or fructose.
The sugars then cross your gut lining and are absorbed into the bloodstream. As your body senses the sugar levels in your blood rising, the pancreas releases a hormone called insulin to help direct the sugars where to go. Simple carbohydrates raise your blood sugar levels quickly, while complex carbohydrates raise them slower. This is especially important if you have diabetes.
Glucose is either shuttled to cells to be used immediately for energy or its sent to the liver to be stored for use later, depending on what your body needs.
Galactose gets turned into glucose in the liver, which is either stored or burned for energy.
Fructose has a slightly different path. It’s sent directly to the liver, where most of it is converted into glucose, some of it can be burned for energy if needed, and a very small portion of it can be converted to fat through a process called de novo lipogenesis (1).
In short, almost all the carbohydrates we eat end up turning into glucose.
So.. is sugar bad for you?
The real problem when we’re talking about sugar is added sugar.
If anyone tries to tell you that you shouldn’t eat fruit because it has sugar in it, you should not take any more nutrition advice from them.
Nobody in the history of the world ever got fat or unhealthy from eating too much fruit.
Period. End of story.
Added sugar can be problematic if it causes you to eat too many overall calories because sugar makes food taste much better.
If you’re wondering how many calories you need for your goals, you can use my calorie calculator below.
Cal’s Calorie Calculator
Foods that have a lot of added sugar generally taste good and are easy to overeat. This doesn’t mean that those foods need to be avoided at all costs, it just means you need to be careful not to overeat them.
Check out the Oreos and the apple below.
One serving of Double Stuf Oreos and one large apple have similar amounts of calories and sugar.
However, it’s easy to have triple the amount of Oreos in one sitting, but it’s pretty unlikely you’ve ever sat down and eaten three apples back to back!
The apple has fiber and micronutrients, which help you feel more full. The Oreos don’t, which makes it easy to polish off an entire sleeve of them.
That doesn’t mean the Oreos are “bad” and the apple is “good”. It just means you need to be careful to not overeat the Oreos if you decide to eat them.
The bottom line on added sugar is that it’s not really bad or good.
As long as you can enjoy foods with added sugar in moderation, there is nothing wrong with fitting them into an overall healthy diet.
Is sugar fattening?
Sugar by itself is not fattening.
The only way to gain body fat is to consistently eat more calories than your body burns.
Just because something has added sugar doesn’t mean it will necessarily be turned into fat. Added sugars from candy and natural sugars from fruit both end up becoming mostly glucose in our bodies.
While it’s true that fructose and glucose can both be converted to body fat through de novo lipogenesis, this does not mean that sugars are fattening! It’s much easier for your body to store dietary fat as body fat because it doesn’t have to convert it to anything.
Studies have shown that when you’re in a calorie surplus, you’ll store more body fat from dietary fats than from carbohydrates (2).
This is because you’re more likely to burn the extra carbs for energy than store them as body fat.
When you’re in a calorie surplus, you’ll still gain fat, but it will more likely be from the dietary fat you eat than the carbohydrates.
So, dietary fat is technically more fattening than sugar is..
When overall calories are controlled for, low added sugar diets don’t lead to more weight loss than high added sugar diets.
This was shown in a study where 20 women were fed a high added sugar diet (43% of calories from sugar) and 22 women were fed a low added sugar diet (only 4% of calories from sugar). At the end of the study, both groups of women had lost similar amounts of weight despite the large difference in added sugar intake (3).
At the end of the day, it’s not sugar itself that’s fattening, it’s eating more calories than you burn.
What about high fructose corn syrup?
High fructose corn syrup gets a bad rap, particularly because the rise in its use correlates with the rise in obesity in the U.S.
However, correlation in two scenarios doesn’t necessarily mean they are related. In most cities, there is a correlation between the amount of ice cream eaten and the amount of crime that takes place.
Does this mean that ice cream causes people to become violent?
Of course not! The reason there is a correlation is because more crime takes place in the summer months, which is of course when more ice cream is eaten.
The real question is whether or not high fructose corn syrup is inherently worse for you or more fattening than regular table sugar.
High fructose corn syrup is part glucose and part fructose. Usually, it’s a little bit higher in fructose than glucose, hence the name “high fructose corn syrup”.
There is also a concern that because fructose is processed in the liver, it is somehow more dangerous than glucose and can lead to the accumulation of fat in liver cells.
Some research in rodents does show that very high amounts of fructose can be converted to fat and lead to a fatty liver (4).
However, the rodents in the study were getting over half of their calories from fructose alone!
This would be extremely difficult to achieve in the real world, since high fructose corn syrup is only about half fructose. The amount of soda you would need to drink for that to happen would be astronomical!
In contrast to the rodent study, there is research in humans showing that when calories are controlled for, fructose is used just like any other carbohydrate in your body.
In one study, subjects were given 150 grams of fructose in addition to their regular diets. To put that in perspective, you would need to drink about 7 sodas or eat 21 bananas to get that much fructose per day!
The participants in the study lost a modest amount of weight and no adverse effects on liver fat or other health markers were observed (5).
This shows that it’s the extra calories from fructose that are the problem, not fructose itself.
Furthermore, the authors of a recent meta analysis (which is a review of all the evidence to date) had this to say:
“In summary, there is nothing unique about the sugar, fructose. It is harmful when in excess but potentially beneficial when taken in small amounts—providing evidence that it is the excess energy that is causing harm and not some unique metabolic effect.” (6)
Is sugar toxic?
The word toxic is thrown around a lot in the fitness and nutrition world, but it’s important to remember that the dose makes the poison.
Too much of anything can kill you in the right dose.
Even water.
So how toxic is sugar, really?
Substances are measured for toxicity with something called a median lethal dose. It’s basically how much of the substance you would need to consume to kill half the population that’s tested.
In this case, the population is rats because, well, it would be pretty unethical to test it on humans..
The median lethal dose for sugar comes out to be around 6 pounds! (7).
So unless you’re consuming anywhere close to 6 pounds of sugar per day, then sugar is not toxic.
Is sugar addicting?
The idea that sugar is addicting in the same way that drugs are comes from more research on rodents.
In one study, rats were given the choice between cocaine and either sugar or a calorie free sugar substitute. Almost all of the rats preferred the sugar or sugar substitute over the cocaine (8).
People then leapt to the conclusion that sugar is more addicting than cocaine.
The problem is that the research was done in rodents, and doesn’t necessarily mean that humans will react the same way. There could be a number of reasons that the rats chose the sugar over the cocaine.
Sugar addiction in humans has not been shown in studies.
In another meta analysis looking at all the evidence of sugar addiction in humans, the authors make the argument that the design of the study could explain why the rodents would choose the sugar over the drugs. They concluded the following:
“We find little evidence to support sugar addiction in humans, and findings from the animal literature suggest that addiction-like behaviors, such as binging, occur only in the context of intermittent access to sugar. These behaviors likely arise from intermittent access to sweet tasting or highly palatable foods, not the neurochemical effects of sugar.” (9)
Think about it.. sugar by itself isn’t all that appetizing.
When was the last time you poured yourself a bowl of Domino’s cane sugar and ended up eating the entire bag? Nobody is selling their belongings and committing crimes to get their hands on pure sugar..
All the tastiest snacks and desserts are a combination of sugar and fat, which is what makes them so good.
I pulled a random homemade chocolate chip cookie recipe from Google so you can see what I’m talking about.
-
- 1 cup salted butter* softened
- 1 cup white (granulated) sugar
- 1 cup light brown sugar packed
- 2 tsp pure vanilla extract
- 2 large eggs
- 3 cups all-purpose flour
- 1 tsp baking soda
- ½ tsp baking powder
- 1 tsp sea salt
- 2 cups chocolate chips (or chunks, or chopped chocolate)
Each batch of cookies has a cup of butter and 2 cups of sugar!
It’s the combination of fat and carbs that make them taste so good, as well as what makes them so high in calories.
How much sugar can you eat per day?
It’s true that sugar isn’t fattening by itself, and you could lose weight and get healthier by eating mostly sugary junk food, as long as you are in an overall calorie deficit. Mark Haub is a nutrition professor at Kansas State University who lost 27 pounds eating a diet made up of mostly junk food.
However, I’m not saying you should eat as much sugar and junk food as you want.
If you are trying to lose weight, limiting the amount of sugary junk foods you’re eating can help you stay full. It’s hard enough to consistently stay in a calorie deficit, and eating a lot of foods that don’t fill you up will only make it more difficult.
You’ll also be missing out on getting enough fiber and micronutrients if your diet is chock full of sugary treats.
So, how much sugar is too much?
A good rule of thumb is that 80-90% of your calories should come from nutrient dense whole foods sources. That means that 10-20% of your calories can be in the form of treats that you enjoy.
As a practical example, let’s say you’re in a calorie deficit and you’re eating 1,800 calories per day.
That means that 180-360 calories per day can come from foods that aren’t so healthy, including sugary treats.
Making room in your diet for some not-so-healthy treats can be a way to increase your adherence to that diet.
You don’t have to eat treats every day, but as long as you account for them you can enjoy them in moderation and not ruin your progress.
Wrapping up
If you got this far in the article, you know that sugar isn’t good or bad by itself, it depends on the context.
In the context of an overall nutrient dense, whole food diet?
A little bit of sugar is not an issue.
However, if consuming sugar is causing you to eat too many calories, you should think about limiting how much sugar you’re taking in.
The take home message is that contrary to what some quacks on the internet would have you believe, you don’t need to be afraid of sugar.
Having a few cookies now and then isn’t toxic. Eating a piece of cake at your nephew’s birthday party won’t magically make you gain fat. You won’t become addicted to sugar by eating a few pieces of halloween candy.
So, eat some sugar in your overall healthy diet if you want to, or don’t.
Either way, there’s no need to be afraid of sugar.