Eating whole, plant-based foods rich in healthy nutrients is the key to living a healthy and long life. Still, how many of us are going to reach for an apple instead of a cookie or cake?

By now, you must have heard all the bad talk about sugar. Processed foods filled with refined sugars are unhealthy and will cause you health issues in the long run. However, all sugar is not the same. You can have sugar in healthy forms as well. Most fruits naturally have fruit sugars, and some vegetables do too.

Nonetheless, you are at the right place to learn about WHY and HOW you can make a healthier choice and say “goodbye” to the processed food. Now, get all your sugar-related questions answered!

 

Sugar Defined

Most people have an idea of what sugar is. Sugar is the thing you add to your food that introduces a warm sweetness that feels like it is hugging your tastebuds.

However, the term sugar means so much more than just sweetness. While it might seem like you are only craving it when you have a sweet tooth, sugar is a significant and essential part of our bodies.

 

Definition

Let’s start at the beginning. Three foremost nutrients supply our body with energy: carbohydrates, protein, and fat. Sugar is the generic name for carbohydrates.

It is an energy-containing molecule, which means that it provides the body with energy (calories) when consumed and metabolized.

There are many different types of carbohydrates- ranging the simple to complex. The most basic forms of carbohydrates are called monosaccharides (a single carbohydrate molecule). The more complex structures are called polysaccharides (multiple carbohydrate molecules attached- such as starch).

The term sugar refers to the two most basic types of carbohydrates. Those are monosaccharides (fructose, glucose, and galactose) and disaccharides (two monosaccharides bonded). More complex chains of three or more monosaccharides are called oligosaccharides. These complex carbohydrates are starches.

 

Different names for sugar

There are 56 different types of sugar used in food manufacturing currently, and they are not always obvious (1). The most commonly recognized sugar molecule in food is sucrose or regular table sugar. Table sugar comes from a plant called sugar cane, which is high in sucrose.

You will often find syrups on ingredient lists, which are sugars that have been extracted from carbohydrate-rich foods and then dissolved in water. Examples include brown rice syrup, maple syrup, or corn syrup.

Another way sugar in processed foods is hidden is with fruit juice concentrates. They are produced by removing most of the water from a fruit juice, leaving a concentrated syrup-like substance.

The food industry tries to market fancy-sounding sugars as more natural than ultra-processed sugars such as high fructose corn syrup. Coconut sugar, date sugar, organic cane juice, and agave nectar are examples of this practice. However, these are all refined sugars at the end!

 

How does the body metabolize sugar?

As mentioned above, the food that we consume is composed of three primary energy sources. However, we can use them only if the body breaks down the nutrients down into a usable energy source.

The chemical reactions and processes in which the body converts food to usable energy are called metabolism.

 

Basic Steps of Metabolism

The digestion of carbohydrates begins in our mouths. When we chew, our teeth mechanically break up the food and coat it with saliva. Then, enzymes in our saliva, such as amylase, begin the chemical digestion process by breaking down the bonds between carbohydrate molecules.

Next, our stomach finishes the mechanical digestion by turning the food matter into a liquid called- chyme to pass into the small intestine. Once in the small intestine, enzymes are released by the pancreas to break down the bonds between carbohydrate molecules.

At the end of this process, there are only singular carbohydrate molecules (monosaccharides) at the end of this process, only singular carbohydrate molecules (monosaccharides) remain. These simple sugars will be absorbed into the bloodstream as galactose, glucose, and fructose and transferred to cells. There they are used for energy.  (2).

 

Insulin

After you eat a meal containing carbohydrates, they are absorbed into your bloodstream and raise your blood sugar level (glucose level). This increase of glucose in the blood triggers the release of a hormone called insulin from our pancreas. The role of insulin is to move the glucose out of the bloodstream and into our cells to use for energy (2,3).

 

Fructose vs. glucose

Fructose is a type of simple sugar, and it is the primary source of sugar in fruit. Our body almost entirely metabolizes fructose in the liver. There it converts to glycogen (the storage form of carbohydrates) and triglycerides (fats) (3).

When compared to glucose, fructose does not trigger the same release of insulin as glucose does. Nonetheless, excess amounts of fructose and glucose can lead to weight gain. Our bodies turn excess glucose into fats. Then our body primarily stores the fat in subcutaneous fat cells as reserves. Fructose converts to fats that deposit in the liver and visceral fat cells (4).

Since fructose is the type of sugar in fruit, you may be wondering how fruit can be healthy. Studies have shown that the source of fructose can have a role in how it affects our bodies. For example, a randomized controlled study published in the journal “Metabolism”, showed that fruit sugar, fructose, does not have the same detrimental effect that fructose from refined foods has. The subjects who consumed fruit had better weight loss results than those who restricted all forms of fructose. (5)

 

Types of sugar found in foods

In our food and drinks, there are two main types of sugar: natural sugars and refined sugars.

 

Natural sugars

Many foods, such as fruits and vegetables, have naturally occurring sugars (fructose and glucose). We call these sugars natural sugars because the sugar is part of the food matrix as it grows in nature.

 

Added sugars and refined sugars

Added sugars, on the other hand, refer to sugars that have been added to a food during processing. Even if the type of sugar added is a naturally occurring sugar, such as honey or maple syrup, the fact it is added to a food classifies it as added sugar.

Refined sugar or processed sugar simply refers to sugar that has been produced and processed from naturally occurring sources such as turning brown rice into brown rice syrup. We would then refer to this brown rice syrup as an added sugar when used as an ingredient in a food product.

 

Fruit Sugar vs. Refined Sugar

Apart from the main points of how these sugar types differentiate, there is also another big difference- the metabolic effect.  Now, we will discuss the metabolic effect of fruit sugars vs. refined sugars.

 

The difference

When we eat foods that naturally contain sugar, such as fruit, in their whole form (eaten in the same way that food comes from the ground), there are multiple steps that the body has to take to digest and extract the sugar from that whole food. These steps allow its nutrients to be absorbed later down in the digestive tract. The additional steps required to digest whole food, cause a slow increase and stabilization of sugar in the bloodstream.

In contrast to when we eat foods that contain refined sugar added to them (processed foods, for example- cupcakes), there is little mechanical digestion that has to occur to separate the sugar from the rest of the ingredients in that food. This sugar passes through our stomach and into our small intestine much more rapidly than the sugar in fruit does and will cause a spike in blood sugar.

This spike in blood sugar signals the pancreas to release a large amount of insulin, usually too much, to quickly bring the blood sugar level down. This results in a low blood sugar response roughly two hours after consumption. This is called “rebound hypoglycemia”.

Rebound hypoglycemia makes the body release fats (lipids) into the bloodstream to compensate. Excess fats in the bloodstream are known as high cholesterol and high triglycerides. If this is happening for long periods, excess fats in the blood may contribute to a higher risk for cardiovascular issues and heart disease.

Eating whole fruit does not trigger this same rebound hypoglycemia that refined sugars do (6).

 

Different forms of fruit

You can have fruit in many different forms- whole, as fruit juice, and as smoothies. They are all still fruits, but are you getting the same benefits from all of them?

 

Whole fruits vs. juices and smoothies

To digest and absorb sugars from fruit, they need to be digested and broken down. There are steps of mechanical and chemical processes that extract the sugars from the fruit.

When the fruit you eat is whole, the digestion process works at a slower pace, and also the glucose absorption into the bloodstream is at a slower pace.  That causes a slow and steady rise of blood sugar levels and causes a controlled insulin response.

When you drink the juice from the fruit, you are not consuming the fiber. If you consume fruit as a smoothie, it is already mechanically processed and partially broken down. In both cases, it means that they will pass through your system faster, and glucose (fructose) will absorb into your bloodstream at a faster rate. That causes a rapid blood sugar spike, which will cause an insulin spike and eventually rebound hypoglycemia. (6)

 

Fruit juice

The primary reason fruit juice leads to a spike in blood sugars in a similar fashion as soda or other sweetened beverages is the lack of fiber. Yes, fruit juice is still more nutritious than soda pop because of the antioxidants and vitamins, but in the end, it is essentially sugar water.

Whole fruit does not spike our blood sugars in the same way that foods or beverages with added sugars do. That is because of its fiber content.  Fiber helps to slow down the digestion of sugar. Fiber, specifically soluble fiber, forms a gel in our intestines which produces this slowing effect (7).

When you turn fruit into juice, all of the fiber is lost. Even in the case of juice with pulp, only a small portion of pulp remains, and it separates from the rest of the beverage, so it does not help slow down the digestion process. So, even though your juice is labelled “no added sugar”, it does not mean the naturally present sugar in that juice is innocent.

 

But, smoothies contain fiber. Aren’t they healthy?

When we blend fruits into smoothies or purees like apple sauce, they contain the same amount of fiber that the whole food version does. Despite this, blending fruit causes a rapid spike in blood sugar and insulin compared to eating the same amount of fruit in its intact form (7, 8).

That is because the smoothie passes through your gut at a faster rate, the mechanical breakdown is quicker. This causes the sugar to be absorbed more rapidly into the bloodstream.

However, as an exception, consuming blended berries does not cause the same rebounding low blood sugar response seen when drinking juice or smoothies as other types of blended fruit (9).

Another issue with the quick transit of smoothies through the system compared to whole fruits is the less time the food spends in your stomach. That will cause you to become hungry sooner after eating. The feeling of hunger is the leading cause of overconsumption of calories and weight gain.

So, smoothies are less optimal if compared to eating whole fruits, especially if your goals are blood sugar control and weight management.

 

When to avoid fruit

While fruits are considered a healthy food, sugar is sugar, even if it comes from fruit. The science behind carbohydrate metabolism suggests there is a limit to how much fruit is advisable to consume.  And, also in what circumstances you need to avoid fruit.

We suggest that fruit consumption be limited or avoided if you have a condition that affects how you metabolize sugar, for example, diabetes.

 

Is there a limit to how much fruit I can eat?

The form you eat the fruit in (whole, blended, or juiced) is the most significant factor. Even then, we do not suggest consuming more than three whole fruits or the equivalent of three cups of fruit per day. That is because of the overall sugar load that even whole fruits contain.

 

Diabetes

For people with diabetes, consuming a lot of sugar is not recommended.

Apart from limiting fruit to three servings per day, we suggest spreading your servings throughout the day and pairing the fruit with other fiber-rich foods for even better blood sugar control.

Berries are lower in overall sugar content and have more fiber when compared to other fruits. For that reason, you can include them in your daily diet more than fruits higher in sugar.

 

Bottom line

The sugar found in whole fruits is very different from refined sugars added to processed foods. The sugars from whole fruits are digesting and absorbing into the bloodstream at a slower pace than added sugars. Whole fruits also contain valuable nutrients such as fiber, vitamins, minerals, and phytonutrients that refined sugars do not.

We recommend having fruit, around 3 servings, daily. We recommend staying away from fruit juice and choosing whole fruits more often than smoothies. Eating a variety of fruit each day is not only good for your overall health, but it is also delicious!

If you are interested in learning how you can transition to eating more plant-based whole foods, you can do that by booking an appointment with Aroga’s Registered Dietitians by email at care@wordpress-600810-1944102.cloudwaysapps.com or by calling +1.888.80.AROGA.

 

References

(1) Book: sugar has 56 names. Robert Lustig, 2013. https://robertlustig.com/56-names-of-sugar/

(2) Goodman BE (2010) Insights into digestion and absorption of major nutrients in humans. Adv Physiol Educ 34:44–53

(3) Softic S, Gupta MK, Wang GX…Kahn CR.  Divergent effects of glucose and fructose on hepatic lipogenesis and insulin signaling NIH external link.  J Clin Invest 127: 4059-4074, doi: 10.1172/JCI94585, 2017.

(4) Stanhope KL, Schwarz JM, Keim NL, et al. Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest. 2009;119:1322–1334.

(5) Madero M., Arriaga J.C., Jalal D., Rivard C., McFann K., Pérez-Méndez O., Vázquez A., Ruiz A., Lanaspa M., Jimenez C.R., et al. The effect of two energy-restricted diets, a low-fructose diet versus a moderate natural fructose diet, on weight loss and metabolic syndrome parameters: A randomized controlled trial. Metabolism. 2011;60:1551–1559. doi: 10.1016/j.metabol.2011.04.001

(6) Torronen R., Kolehmainen M., Sarkkinen E., Mykkanen H., Niskanen L. Postprandial glucose, insulin, and free fatty acid responses to sucrose consumed with blackcurrants and lingonberries in healthy women. Am. J. Clin. Nutr. 2012;96(3):527–533.

(7) Haber G.B., Heaton K.W., Murphy D., Burroughs L.F. Depletion and disruption of dietary fibre. Effects on satiety, plasma-glucose, and serum-insulin. Lancet. 1977;310:679–682

(8) Martens MJI, Westerterp-Plantenga MS (2012) Mode of consumption plays a role in alleviating hunger and thirst. Obesity (Silver Spring) 20: 517–524.

(9) Torronen R., Kolehmainen M., Sarkkinen E., Poutanen K. Berries reduces postprandial insulin responses to wheat and rye breads in healthy humans. J. Nutr. 2013;143(4):430–436