Fruit is bursting with vitamins, minerals, and phytonutrients. Plus, most fruit, from berries to apples, are a good source of fiber and carbohydrates for energy. In fact, noshing on a piece of fruit after a workout is a healthy way to replace muscle glycogen stores and help your muscles recover after a sweat session. Fruits taste naturally sweet and delicious, but some people complain that they feel hungry after eating a piece of fruit, more so than when they eat a more balanced and substantial snack. Can eating fruit increase hunger and boost the desire to eat more food later in the day?
Hunger, Satiety, and Fruit
The carbohydrates in fruit are of two types–glucose and fructose. Most common fruits contain varying amounts of these two sugars. Table sugar, also known as sucrose, is made up of roughly equal quantities of glucose and fructose. Yet there are differences in how the body metabolizes these two sugars. When you eat something with table sugar, your body breaks the sugar down into glucose and fructose. Glucose stimulates the release of insulin to help cells take up the glucose and reduce the amount of glucose in the bloodstream. In contrast, fructose doesn’t provoke insulin release. Instead, fructose travels directly to the liver where the liver metabolizes it.
Do these sugars have differing effects on appetite and satiety? A study published in the Proceedings of the National Academy of Sciences suggests that they do. In the study, they asked 24 subjects to ingest either glucose or fructose while they looked at appetizing pictures of food. As they gazed at the photos, they asked the participants to rate their hunger. Interestingly, the subjects rated their hunger levels higher when they consumed fructose as opposed to glucose. So, fructose in any form may not be as satisfying relative to glucose.
Why might consuming fructose not satisfy hunger as much as glucose? Studies show that the insulin release that happens when you consume glucose suppresses appetite. Research also reveals that brain activity in areas of the brain that control appetite show less activity after consuming a source of glucose. So, the brain doesn’t go into overdrive in an effort to get you to eat more.
In contrast, fructose doesn’t stimulate insulin release. Therefore, the hormonal response to fructose differs from that of glucose. You don’t get the release of insulin that signals your brain that you’ve had your sugar and are full. Therefore, there’s less appetite suppression when you consume something high in fructose, including natural sources of fructose, like fruit. Some research also shows smaller rises in glucagon polypeptide one and leptin after consuming fructose. That’s important because these hormones suppress appetite.
However, not all studies show that fructose causes less satiety than glucose. Why the discrepancy? The results may differ between studies because of differences in how the participants consumed the sugars, whether it was in food or liquid form, and how they measured satiety.
Eat Fruit with a Source of Protein
Irrespective of whether glucose or fructose is more satiating, fruit contains both glucose and fructose in varying ratios. Although fruit also has fiber to reduce the blood glucose response and slow the rate at which fruit moves through the digestive tract, it still moves relatively quickly and can leave you feeling hungry an hour or two later.
One way to avoid those hunger pangs is to eat fruit with a source of protein. The protein further reduces the blood sugar response to a meal or snack and boosts satiety while fat slows the movement of the fruit through the digestive tract so that you feel fuller. That’s why biting into an apple with almond or peanut butter on it or eating that apple with a handful of nuts is more satiating than munching on an apple alone. Nut butter and nuts contain both protein and fat.
The worst approach is to get your fruit by sipping on a glass of fruit juice. Fruit juice is a concentrated source of fructose and glucose and lacks the fiber needed to slow absorption of the sugar and prevent blood sugar spikes. So, your blood sugar rises quickly and falls just as rapidly and you’re hungry again after only an hour or two. Dried fruit is another type of fruit to avoid since the fruit is dehydrated. Therefore, dried fruit is a concentrated source of sugar, including fructose.
Even worse is consuming high-fructose corn syrup, a controversial fructose sweetener in many packaged products. High fructose corn syrup is made from corn starch and contains higher amounts of fructose relative to glucose. Some studies link high-fructose corn syrup with insulin resistance, the progression of non-alcoholic fatty liver disease, and elevated triglycerides. However, all sugar may be addictive to some degree, at least in animal studies. So, stick to whole fruit and enjoy it with a healthy source of protein.
Are Some Fruits More Satiating Than Others?
If fruits high in fructose suppress appetite less than those that contain mainly glucose, some might be more satiating than others. Fruits higher in fructose include dried fruits, apples, sweet cherries, grapes, and pears. Fruits that are lower in total sugar are avocado, berries, guava, lemon, lime, papaya, peaches, and starfruit. The most satiating fruits would likely be ones that are low in fructose and low in total sugar. However, you increase the satiety benefits by consuming fruit as part of a meal or at least with a source of protein and fat, like nut butter. Berries with low-sugar yogurt is another healthful and tasty way to enjoy fruit with a source of protein and fat.
The Bottom Line
Eating fruit, especially fruit high in fructose, as a snack may not be as satisfying as eating a snack that includes protein. Don’t forget, protein is the most satiating macronutrient! But fruit is packed with vitamins, minerals, phytonutrients, and fiber. So, to maximize satiety, enjoy your next piece of fruit with some nut butter, yogurt, or another source of protein rather than eating it by itself – and avoid fruit juice.
References:
· Nutr Metab (Lond). 2012; 9: 89.
· Food and Chemical Toxicology. Volume 118, August 2018, Pages 190-197.
· Current Opinion in Behavioral Sciences. Volume 9, June 2016, Pages 111-117
· Science Daily. “Could eating fruit be making you hungrier?”
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