Sucrose vs Glucose vs Fructose: What’s the Difference

Sugar is one of the most common carbohydrates found in nature. There are many types of sugar, which include honey, fruit juices, cane juice, maple syrup and others. Sugar is a simple carbohydrate with two sugars (glucose and fructose) bonded together.

Fructose is sweeter than glucose and it occurs naturally in fruits such as apples or pears.

Glucose is the main energy source for your body. It provides fuel to all cells in your body including those that produce hormones and enzymes. Your liver converts glucose into glycogen stores where it can be used later during exercise or when needed for other purposes like storing fat. When you eat food, glucose enters your bloodstream through your digestive tract and travels to various parts of your body where it is stored there until required again.

The amount of glucose in your blood determines whether you feel hungry or full. If too much glucose enters your bloodstream, it causes a spike in insulin levels. Insulin helps regulate blood sugar levels throughout the day and prevents excessive hunger. Too little insulin and blood sugar will remain low, resulting in feeling tired or even lethargic. High blood sugar may cause headaches, confusion and seizures.

Sucrose, also known as table sugar is a carbohydrate made up of glucose and fructose. It is often used in cooking and baking or as a sweetener.

Your body digests carbohydrates into simple sugars, such as fructose and glucose, and these are absorbed into your blood stream. There, the fructose can be metabolized quickly, providing instant energy, while the glucose is processed more slowly, releasing its energy over a longer period of time.

Why is this important?

If you consume carbohydrates which are high in fructose, such as honey or apples, your body will experience a spike in your blood sugar level, causing an insulin release.

The combination of a spike in blood sugar followed by a sudden drop often results in the “rush” or “high” feeling that you get after eating sugary foods. Other foods which may cause similar spikes and drops in your blood sugar levels include potatoes, white bread and even milk. Any food which is high in carbohydrates may also have a similar effect.

Sugar has been accused of being one of the main causes of diabetes, heart disease and even obesity. Many people claim that eliminating sugar from their diet results in weight loss, clearer skin and better overall health. While these claims are still under debate, there is no denying that eating too much sugar can lead to health complications in the long run.

Is Sugar Bad For You?

The World Health Organization recommends that you limit the amount of added sugars in your diet to a maximum of 10% of your daily calories. This means that if you eat 2000 calories per day, the most sugar you should have is 200 grams. The United States Department of Agriculture recommends a maximum of 35% of total calories per day from sugar. So, if you eat 2000 calories per day, the most sugar you should have is 700 grams. Keep in mind these values are for ADDED sugars only. The sugars that are present in fruits and vegetables are fine in any amount as long as you’re eating a balanced diet.

For most adults, no more than 50 grams of sugar (equivalent to 10 teaspoons or just under 2 tablespoons) should be consumed per day. This is especially important if you are overweight, have diabetes, high blood pressure or heart disease.

The biggest problem with sugar and our modern diet, however, isn’t that we’re consuming too much sugar. It’s that the sugars we are consuming are “empty calories” or “nutritionally void”. The biggest source of added sugars in our diet is fructose in the form of corn syrup and sucrose (table sugar). These are added to ordinary, every day foods such as bread, breakfast cereals and even milk.

One of the most common complaints that I hear from my patients is that they’re hungry all the time. This is especially true for people who follow low-carbohydrate diets which are currently popular. These diets are great for quickly losing weight due to their ability to put the body into a metabolic state called ketosis. Unfortunately, this also has the effect of making the body extremely metabolically efficient, meaning that not many calories are necessary for basic body function.

This causes people to EAT all the time because their bodies are literally starving. This isn’t because they have some disease that causes them to eat constantly (such as Prader-Willi). It’s simply due to the fact that they aren’t getting enough calories, or more importantly ENOUGH CALORIES OF THE RIGHT KIND!!!

Here’s a little experiment you can try: Eat ONLY sugar and starch, (pasta, bread, potatoes etc) for one month. Don’t eat anything else except for meat, dairy and fats. You can add some supplements if you like, but other than that it’s just sugar and starch three times per day. Take in an amount of energy equal to what you normally eat. You should lose weight rather quickly because you’ll be restricting calories.

After one month, stop the experiment and see how you feel. I predict that you’ll end up feeling like crap. You might have constant cravings, your mind will likely be foggy and you may even have some physical discomfort like stomach aches. Most important of all, you won’t be OPTIMAL.

Your body is not designed to solely burn sugar. It is designed to burn a mix of sugar, proteins and fat. By only burning sugar, your body is not functioning at an optimal level. It’s like putting premium gas in your car but never changing the oil. Sure, you’ll go faster for a little while, but soon your car is going to break down and eventually stop working all together.

This is what’s known as “detrimental stress”.

Stress on the body that doesn’t allow it to adapt and eventually causes damage. The stress of constantly breaking down carbohydrates causes a lot of damage in the long term. This is why so many people have problems with their teeth on high carb diets. This is also why people who eat a diet high in fat don’t have these problems. The body burns the fats, extracts the necessary nutrients and then taps out the remainder as waste.

It’s more or less the perfect metabolic machine. The problem is that our culture (and most others) have brainwashed us into believing that sugar is good and fat is bad.

So how much sugar is too much?

Well, that all depends on the person. Some can tolerate more than others. It also depends on what you consider “sugar”. If you limit your intake of sugary foods to only fruits then you’ll be getting a lot more nutrients and therefore can consume more of it. However, if you also include things like candy, cake and soda, then you’re really doing damage to your body. At some point this begins to damage your body in ways that aren’t easy to fix.

The bottom line is that we don’t need sugar to survive. We evolved without it and there are plenty of cultures that still don’t have much contact with the stuff. It’s not a necessary part of the human diet.

How To Know If You’re Eating Too Much Sugar

So how can you tell if you’re eating too much sugar?

There are some obvious clues like having a soda every now and then or indulging in dessert once a week. However, there are also some less obvious clues like drinking fruit juice or eating foods that are “low fat”, but in reality are just replacing fat with sugar (I’m looking at you yogurts and low fat dairy products).

Sources & references used in this article:

Sucrose, high-fructose corn syrup, and fructose, their metabolism and potential health effects: what do we really know? by JM Rippe, TJ Angelopoulos – 2013 –

Straight talk about high-fructose corn syrup: what it is and what it ain’t by JS White – The American journal of clinical nutrition, 2008 –

Endocrine and metabolic effects of consuming beverages sweetened with fructose, glucose, sucrose, or high-fructose corn syrup by KL Stanhope, PJ Havel – The American journal of clinical …, 2008 –

The comparative nutritive values of glucose, fructose, sucrose and lactose when incorporated in a complete diet by HH Mitchell, TS Hamilton, JR Beadles – The Journal of Nutrition, 1937 –

Serum-fructose levels after sucrose or its constituent monosaccharides by I Macdonald, LJ Turner – The Lancet, 1968 – Elsevier

The effects of four hypocaloric diets containing different levels of sucrose or high fructose corn syrup on weight loss and related parameters by J Lowndes, D Kawiecki, S Pardo, V Nguyen… – Nutrition Journal, 2012 – Springer

Hepatic adaptations to sucrose and fructose by ME Bizeau, MJ Pagliassotti – Metabolism, 2005 – Elsevier

Fructose acute effects on glucose, insulin, and triglyceride after a solid meal compared with sucralose and sucrose in a randomized crossover study by C Gallagher, JB Keogh, E Pedersen… – The American Journal …, 2016 –