Too much sugar is bad for your health. Many people believe that simple carbohydrates (like white bread and white rice) are worse than complex carbohydrates (like fruits and vegetables). But which one is worse? Should you avoid both of them?

It’s currently a lot of controversy whether high fructose corn syrup (HFCS) is really worse than regular table sugar (sucrose). Some say that it causes more stress on the body, while other say that it’s fine whether it’s glucose or fructose. The truth is that it’s a combination of both and no one is completely safe.

It’s time to find out if you’re one of the millions of people who are cutting out sugar, or are one of the millions of people who want to start. In this article I will compare and contrast the two forms of sugar known as glucose and fructose. Fructose is the sugar found naturally in fruit, such as apples and oranges, where it is known as sucrose. Fructose is also the sugar contained in high fructose corn syrup (HFCS), which is the type of sugar our food and beverage industries use to increase the sweetness of their products.. Read more about fructose vs glucose metabolism and let us know what you think.

What’s the difference between fructose and glucose? When it comes to gaining body fat and lowering our insulin sensitivity, what is worse? Today, we’ll take a look at a research that tries to address this issue.

Many of you have most likely seen pro-high fructose corn syrup advertisements (if not, here is a link to one on YouTube).

They irritate me, partly because they’re so cheesy, but also because they attempt to reassure you by claiming that high fructose corn syrup isn’t any worse for you than sugar.

Until recently, it was unclear which was the worst. One research claims that high fructose corn syrup is harmful, while another claims that there is no difference. Are we, however, asking the correct question? Should the question be, “Which is Worse?”

While people argue over who is the worst, the actual issue is how much sugar you consume. In the year 2000, the typical American diet included 15.8% sugar (by calories). [1] That’s the average, which means that a lot of individuals consume more calories than that.

That’s the part I don’t get. We all know that too much sugar, no matter what type, is harmful for you, but that hasn’t prevented people from eating/drinking a lot of it. Sugar consumption, therefore, is the actual problem.

The research I’m looking at this week contrasts how terrible glucose is compared to fructose, but if you ignore the differences, you’ll see how horrible it is to consume a lot of sugar (up to 25% of your diet).

The goal of this week’s research is to address a few concerns regarding sugars:

  1. Is there a difference between consuming fructose and glucose in terms of weight gain? Is there a difference between the two sugars in terms of weight gain?
  2. When compared to glucose, can fructose induce dyslipidemia (negative changes in blood lipids)?
  3. Is fructose consumption associated with a reduction in glucose tolerance and insulin sensitivity?

KL Stanhope, et al. In overweight/obese individuals, drinking fructose-sweetened drinks rather than glucose-sweetened beverages increases visceral adiposity and lipids while decreasing insulin sensitivity. Journal of Clinical Investigation April 2009 [Epub before print]


Overweight/obese individuals were assigned to one of two groups: glucose or fructose. Body composition, blood pressure, calories eaten each day, blood measurements (lipids, insulin, and glucose), and rates of lipogenesis (fat formation) were all assessed over the course of two weeks.

  Glucose Fructose
Measurement Men Women Men Women
the number of participants 7 8 9 8
Age is a factor (years) 54± 3 56± 2 52± 4 53± 2
the amount of weight (kg) 88.4± 2.9 84.0± 4.5 89.3± 2.9 81.9± 4.2
BMI (kg/m2) is a measure of how healthy a person is. 29.3± 1.1 29.4± 1.3 28.4± 0.7 30.3± 1.0
Circumference of the waist (cm) 98.9± 2.6 91.0± 4.0 97.3± 3.3 91.8± 4.4
Fat in the body ( percent ) 29.4±1.1 43.2±1.5 28.5±1.3 39.6±2.2

There were no significant differences in measurements across the groups – this is crucial!

Please pass the Kool-Aid.

The volunteers were allowed to go home and sip Kool-Aid after two weeks of being probed and prodded. Kool-Aid, of course! They ate their regular diet plus Kool-Aid three times a day, not just Kool-Aid.

The sweetener in the Kool-Aid was either glucose (in the glucose group) or fructose (in the fructose group). The Kool-Aid was calculated to represent 25% of each participant’s baseline calorie intake.

So, if a person usually consumes 2000 calories per day, they would consume 500 calories of Kool-Aid on top of that. For ten weeks, I drank Kool-Aid three times a day. I’m hoping they received a variety of flavors.

This research is excellent, in fact, but I’m shocked it was approved by an ethics board (the regulatory people who let you do experiments on people or animals.)

Why? Because these individuals were already overweight or obese, they were placed on a 10-week diet that was 25% more than what they were consuming before they became fat.

And the researchers already know that there will be more fat, less insulin sensitivity, and higher blood lipid levels; they simply want to know which sugar is worse (glucose or fructose).

It doesn’t seem to be a good concept. My best guess is that it was permitted because the participants were required to remain in the hospital for the last two weeks of the Kool-Aid intervention for monitoring and testing.


Surprisingly, eating 25% more sugar calories than you usually do for 10 weeks results in weight gain. What strikes me as surprising is how little weight they gained: 1.55 kg (3.9 lb) for the glucose group and 1.20 kg (2.63 lb) for the fructose group.

In the glucose and fructose groups, total fat rose by just 1.0 kg and 0.8 kg, respectively.

Both groups gained abdominal fat, but the fructose group gained more total abdominal fat and visceral fat (8.6 percent total and 14 percent visceral). Eating a lot of either sugar resulted in weight gain.

The researchers next looked at blood lipids, such as triglycerides and cholesterol. Over the course of 24 hours, fructose raised average triglycerides more than glucose, although both increased triglycerides.

Fasting cholesterol increased in both groups, but the fructose group had a greater increase. Fasting LDL (low density lipids) increased in both groups, with the fructose group increasing more, while HDL decreased in the glucose group while increasing in the fructose group.

Insulin sensitivity and glucose tolerance did not alter in the glucose group, but they did in the fructose group, as did fasting glucose and insulin blood insulin levels.


This research may be seen in two ways:

  1. I should avoid fructose as much as possible. It’s not good for me… Wait, doesn’t fruit include fructose?
  2. Or, consuming a lot of any sugar is bad for me, and I should limit my intake of simple sugars.

What you should take away from this research, in my opinion, should be the second way of looking at it. Sugar consumption will, sooner or later, result in health issues.

In science, there’s a dirty little secret that if your research finds no difference between groups, it won’t be published. It’s almost difficult to publish with the same outcomes if it’s previously been published.

Something fresh and interesting is required. As a result, you must search for distinctions, particularly important ones. Is there a difference between consuming a high-glucose diet and a high-fructose one? Yes. Was the purpose of the research to determine whether or not there are differences and, if so, what sort of differences there are? Yes.

So, after reading this research, you may say to yourself, “I’ll avoid all fructose and consume glucose instead; that way, I won’t have any issues with cholesterol, insulin sensitivity, or visceral fat!”

Then you’ll be in big trouble fast, since the truth is that there’s a bigger difference between no sugar and glucose versus fructose.

How much fruit would you have to consume in order for it to be considered “bad” for you?

Let’s put things in perspective before you quit eating fruit or establish a religious cult to rescue people from the hidden evil in fruits.

First, fructose accounted for 25% of the caloric intake (total calories eaten) in this research. So, if you consume 2000 calories a day, you must consume 500 calories from fructose; if you consume 4000 calories, you must consume 1000 calories from fructose.

That’s a significant amount of fructose. In any case, I wouldn’t suggest consuming so many calories from simple carbohydrates.

Second, if you consider how much real fruit you’d have to consume to reach 500 or 1000 calories of fructose, you’ll see how little you have to be concerned about if you consume fruit in moderation. Look at the table to see how much fructose is included in different foods.

With a few exceptions, most fruits have less fructose than glucose. Foods containing more fructose than glucose, according to the USDA database [2], include:

Food g/100g Fructose (cals) g/100 glucose (cals)
Sucrose 50 (200) 50 (200)
Apples 5.9 points (23.6) 2.4 (9.6)
Pears 6.8 (24.8) 2,8 (11.2)
Juice from fruits 5–7 (20-28) 2–3 (8-12)
Raisins 29.8 percent (119.2) 28.7 (111.2)
Honey 40.9 % (163.6) 35.7 percent (142.8)
Corn syrup with a high fructose content 55-90 years old (220-360) 45 – 10 (180-40)

Let’s see how 500 and 1000 calories of fructose seem in real life:

Food How much fructose do you need to consume to get 500 calories? (25 percent of 2000 calorie diet) How much fructose do you need to consume to get 1000 calories? (25 percent of a 4000 calorie diet)
Sucrose 250 mL (42 teaspoons) 500 mL (84 teaspoons)
Apples Over 20 Over 40
Pears Over 20 Over 40
Juice from fruits Almost 9 quarts of apple juice 17 gallons apple juice
Raisins 420 grams (0.93 pounds) 840 grams (1.86 pounds)
Honey More than 305 g (over 14 teaspoons) More than 610 g (over 28 teaspoons)
Corn syrup with a high fructose content 227 g 139 g 139 g 139 g 139 (23-28 teaspoons) 454 g 278 g 278 g 278 g 278 (46-76 teaspoons)

To get to the amount of fructose seen in this research, you’d have to consume a lot of fruit – more than 20 apples or pears. I’m not sure why I chose apples and pears. They have the most fructose of any fruit.

Berries, citrus fruits, and stone fruit (peaches, plums, and so on) contain less fructose, so you’d have to consume even more of them!

Even if we consider soda pop, which has 39 g (9 teaspoons) of high fructose corn syrup in a 355 mL can — half of which is fructose (19.5g) — you’d need to consume 6.4 cans (2.27 litres) to consume 25% of your daily caloric intake (assuming 2000 calories is your total intake).

Granted, it is conceivable to consume more than 2 litres of soda pop in a single day; nevertheless, I’ve seen individuals consume 10 cans in a single day and vibrate while studying. Though I’ve never seen someone consume 20 apples in a single day… I don’t believe I’ve ever seen anybody consume 20 in a week (about 3 each day).


To summarize, fructose causes greater intra-abdominal fat accumulation, lowers insulin sensitivity, and raises cholesterol in overweight and obese individuals than glucose, although glucose causes fat gain and raises cholesterol as well.

Should you avoid fruit? No, just don’t eat too much of it.

Should you avoid processed sweets and soft drinks? Yes, this shouldn’t come as a surprise to anybody.

Is fructose more harmful to your health than glucose? Yes, to a degree, but both are undesirable.

Should you count fructose grams if you follow PN? No, if you stick to PN 90 percent of the time, you’ll be OK. I’m assuming you’re not hooked up to an IV and drinking soda pop for 10% of your meals.



To see the information sources mentioned in this article, go here.

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Fructose is an added ingredient in most processed foods and some drinks, and people tend to consume a lot of it. On the other hand, glucose is found in most fruit and vegetables and is used by the body for energy. Some people tend to overeat glucose, others tend to overeat fructose, but both are bad for our health.. Read more about sucrose vs glucose and let us know what you think.

Frequently Asked Questions

Is glucose worse than fructose?

Glucose is a sugar that is found in many fruits and vegetables. Fructose is a sugar that is found in honey, fruit juices, and other foods.

Why is fructose more fattening than glucose?

Fructose is a sugar that is naturally found in fruit and honey, while glucose is a sugar that is naturally found in vegetables. When the body breaks down fructose, it produces more fat than glucose does.

Why is fructose the worst?

Fructose is a type of sugar that is found in fruit. It has been linked to obesity, diabetes, and heart disease.

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  • fructose vs glucose metabolism
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