Most everyone agrees that eating fruit is good for you. Whether fresh, frozen, canned, or dried the United States Department of Agriculture (USDA) recommends 2 servings of fruit per day(1) while the American Heart Association (AHA) recommends 4 servings per day(2).
Fruit is high in fiber and low in sugar, naturally filling, and contains many important vitamins and minerals. A medium-sized banana contains roughly 3 grams of fiber, is around 100 calories, and is a good source of potassium, B vitamins thiamine, riboflavin, and niacin, folate, and vitamin C(3).
Sounds pretty good so far, but there is a lot of controversy around bananas. For years, the popular belief was that bananas are good for you. They are sweet and filling, they can help you recover from strenuous exercise, and can help eliminate muscle cramps. Bananas are a versatile food that can be used to combat both diarrhea and constipation.
In recent years, bananas have become reviled by some as a food that you absolutely can not eat if you want to lose weight or be thin. They have been blamed for causing weight gain, gas, and painful bloating. But with no fat and only 100 calories per serving, how has the fruit that looks like a smile gotten turned upside down into a frown?
Nutritional Facts
When choosing what food to eat, it is important to examine the nutritional information on the label. Along with the list of ingredients, you will find detailed information about how many calories, grams of carbohydrates, sugars, protein, and fat each serving contains. These are all important facts to know in assessing the potential health benefit or detriment of the food item. However, whole, unprocessed foods such as fruits, vegetables, and meats rarely have a nutrition label attached to them.
That’s not to say that the nutritional information of these foods is irrelevant or unimportant; what it means is that it is up to the consumer to seek out the information. This can actually be a good thing, if you know what to look for.
Carbohydrates vs. Sugars
When it comes to our favorite fruits, most people would agree that they prefer fruit that is sweet to the taste. When you compare the number of grams of sugar in different types of fruit, you will see that there is quite a range of sugar content.
But there is a problem. Looking at the number of grams of sugar does not tell you whether those sugars are fructose, glucose, or sucrose; that is why nutritional labels also list carbohydrates. The term carbohydrate was developed to differentiate the effect the different types of sugar has on our blood glucose level, i.e. simple or complex carbohydrates. Unfortunately, most labels aren’t specific about which type of carbohydrate it is listing. What is a consumer to do? Hang on, there’s more.
Through clinical testing, it soon became apparent that carbohydrates do not affect the blood glucose level of all people in the same way. So, further testing was done on individuals to find a way to standardize a measurement of a food’s effect on blood glucose levels.
The Birth of the Glycemic Index
During clinical testing, it was discovered that testing a person’s blood glucose level after consuming 50 grams of carbohydrate gave them a controlled standard to compare the person’s blood glucose level after eating a particular food. The lower the glycemic index (GI) rating the less effect it has on blood glucose levels(4).
After plotting a curve of blood glucose levels taken before and several times after eating, plus some fancy calculations the glycemic index became the new way to look at the health potential of food. Even the American Diabetes Association has adopted the glycemic index as their main tool for educating people on how to control their blood glucose level.
Let me give you an example why all of this, so far, is relevant. Let’s compare three popular fruits—watermelon, banana, and navel orange. One serving of watermelon has 18 grams of sugar. One serving of banana has 17 grams of sugar. One serving of navel orange has 23 grams of sugar(5). When comparing sugar content, the watermelon and banana look very similar.
When calculated on the glycemic index, watermelon has a GI rating of 76, which is equal to that of a donut; the banana, on the other hand, has a GI rating of 55, while the orange comes in last with a GI rating of 42. How is it that the fruit with the highest content of sugar (the orange) has the least effect on blood sugar? That has to do with the type of sugar and the amount of fiber these fruits contain.
Glycemic Load Is Better
The glycemic index is a little bit deceiving because it is not based on testing done with the same serving size as outlined by the USDA. To make more relative sense of the data in the glycemic index, the glycemic load (GL) rating was developed. Glycemic load is a calculation based on the glycemic index rating, the USDA serving size, and takes into consideration the amount of carbohydrates in one serving(6).
What the glycemic load tells us is how much we can expect one serving to affect our blood sugar when eaten on an empty stomach. A GL rating of ≥20 is high, 11-19 is intermediate, and ≤10 is low.
Interestingly, watermelon and oranges contain only 11 grams of carbohydrates per serving, while bananas contain 24 grams per serving. The GL of one serving of watermelon is 8, making it a good choice for those watching their blood glucose level. The GL of one serving of orange is 5, making it an excellent choice for diabetics and others with high blood sugar concerns. The GL for banana is 13, making it OK for most people, including diabetics as long as other sources of sugar are kept low. One thing to keep in mind is that the more ripe a banana is, more of its starch turns into sugar. A greener banana will have less of an effect on blood glucose levels than a very ripe one.
Let’s take a moment to recap what we know so far about bananas. Bananas are naturally sweet and are a good source of potassium, B vitamins, and vitamin C. They are fat free and a medium sized banana is about 100 calories. Due to 3g of fiber and 24g of carbohydrates, bananas are filling.
Now, to address the two opposing myths concerning weight. Regular consumption of bananas in addition to your regular diet can cause weight gain in those who are not physically active enough to burn them off. When they are eaten in place of other high carbohydrate foods such as rice, pasta, bread, and most processed foods (including cereals), they will not cause weight gain.
If a banana is consumed with food that is high in protein and fat, the sugars in the banana are more slowly broken down and will have less of an effect on blood glucose, and you will feel full longer. You can add a banana to your high protein breakfast or have it as a snack with nuts or a nut butter. Bananas are great for helping you recover from strenuous exercise; and the potassium can help relieve muscle cramps. Just remember to substitute the banana for other high carb foods if you want to lose weight, or add them to your regular diet if you are needing to gain weight. Are bananas health food? Yes!
More Myths
Just for fun, I am going to tackle a few other myths about bananas. Does eating bananas make you more attractive to mosquitoes? Possibly. What we know about mosquitoes is that they are attracted to heat, sweat, and lactic acid. Exercising outside during peak mosquito activity is likely to garner a few extra mosquito bites. Lactic acid is released by your body during strenuous exercise. It takes about an hour for your body to clear it from your blood once you stop exercising. During this time, you are more likely to attract mosquitoes. Furthermore, foods high in potassium, like bananas, help your body to get rid of lactic acid(7).
However, there are causes other than strenuous exercise that can elevate lactic acid in your blood. Lactic acidosis is the term for an unresolved build up of lactic acid. A few causes include heart attack or heart failure, sepsis, severe lung disease, liver or kidney disease, cancer, diabetic ketoacidosis, and certain medications such as metaformin(8). You will have to decide for yourself if the banana you ate is to blame for you getting bitten. If you have lactic acidosis, you may be keeping your companions from being bitten by attracting all of the mosquitoes for yourself! (Also another popular belief).
Do bananas cause constipation or help alleviate it? That really depends on how hydrated a person is. The soluble fiber in bananas absorb water in the intestines and slows down digestion. For someone who is not properly hydrated, this can lead to minor constipation. On the other hand, for someone who is properly hydrated, the insoluble fiber in bananas will add bulk to your stool and help move things right along in your intestines. For someone with diarrhea, the soluble fiber may help by absorbing water in the intestines.
Lastly, are bananas bad luck to take on a boat? If you dig deep into history, you will find many accounts of ill-fated ships hauling bananas across the ocean. Some of the tragedies aboard banana boats may have be due to the presence of venomous spiders hidden in the bananas as they were brought onboard. Some banana ships may have run into trouble due to the speed with which they had to travel to ensure that their cargo did not rot on the way. And apparently, bananas float in the water, so of all the boats that sank it was always easy to tell where a banana boat sank; instead of vanishing in anonymity and without a trace, banana boats always left a visible sign of their fate(9).
I’m glad you stuck with me until the end. Hopefully you learned something and had a little fun along the way.
References
1. All About the Fruit Group. (2018, January 03). Retrieved from United States Department of Agriculture: https://www.choosemyplate.gov/fruit
2. Fruits and Vegetables Serving Sizes. (2017, January 18). Retrieved from American Heart Association: https://healthyforgood.heart.org/add-color/infographics/fruits-and-vegetables-serving-sizes
3. Anne, M. (n.d.). What Nutrients Do Bananas Provide? Retrieved from SF Gate: Healthyeating.sfgate.com/nutrients-bananas-provide-3330.html
4. Higdon, J., Drake, V., & Delage, B. (2016) Glycemic Index and Glycemic Load. Retrieved from Oregan State University: lpi.oreganstate.edu/mic/food-beverages/glycemic-index-glycemic-load
5. Fruits. (n.d.). Retrieved from Sugar Delirium Blog: www.sugarstacks.com/fruits.htm
6. Greenberg, R. (2011, August 29). Glycemic Load and Glycemic Index: What’s the Difference and Why Does it Matter? Retrieved from Huffington Post: https://www.huffingtonpost.com/riva-greenberg/gl-and-gi_b_863126.html
7. Jorgustin, K. (2018, May 21). 8 Things That Attract Mosquitoes. Retrieved from Modern Survival Blog: https://modernsurvivalblog.com/health/8-things-that-attract-mosquitoes/
8. Lactic Acidosis. (2018, February 28). Retrieved from Drugs.com: https://www.drugs.com/cg/lactic-acidosis.html
9. Simonds, J. (2015, January 2). Top 5 Myths About “No Bananas on Board” Your Fishing Boat. Retrieved from Salt Strong: https://www.saltstrong.com/articles/top-5-myths-no-bananas-aboard-fishing-boat/
