Bananas - the pros and cons of living off them

Question

I have a lot of bananas at the moment. I am cooking them, eating them in so many ways it is impossible to explain. However, is it possible to live off bananas in my vegetarian diet? Am I getting enough nutrients? What should I add to my banana diet, if anything?

Answer 1

Here's what's in 100g of banana according to Wikipedia (percentages based on recommendations for adults)

Nutritional value per 100 g (3.5 oz)
Energy  371 kJ (89 kcal)
Carbohydrates   22.84 g
Sugars   12.23 g
Dietary fiber   2.6 g
Fat   0.33 g
Protein   1.09 g

Thiamine (B1)   (3%) 0.031 mg
Riboflavin (B2)  (6%) 0.073 mg
Niacin (B3)  (4%) 0.665 mg
Pantothenic acid (B5)   (7%) 0.334 mg
Vitamin B6  (31%) 0.4 mg
Folate (B9) (5%) 20 μg
Choline (2%) 9.8 mg
Vitamin C   (10%) 8.7 mg

Iron    (2%) 0.26 mg
Magnesium   (8%) 27 mg
Manganese   (13%) 0.27 mg
Phosphorus  (3%) 22 mg
Potassium   (8%) 358 mg
Sodium  (0%) 1 mg
Zinc    (2%) 0.15 mg

Other constituents
Water   74.91 g
Fluoride    2.2 µg

So you'd need to eat 5kg of banana to meet your daily requirement of iron and zinc, for example, and you would soon become ill due to deficiencies of vitamins A, B12 and E. If you were a fairly active 32 year old woman 170cm tall and weighing 55kg, then you'd need something like 50g of protein a day as a minimum to prevent illness, so you would need to eat 5kg of banana to get that, even assuming (wrongly) that this quantity of banana protein could provide all the essential amino acids in adequate amounts. Bananas also fail to provide calcium. And note the imbalance of sodium and potassium - I hope you like salted banana...

In addition to bananas, consider eating foods that provide iron, calcium, zinc, vitamin A and E and protein, such as a variety of grains, nuts and seeds, dark leafy greens, carrots, mango or sweet potato, beans and lentils. And don't forget your B12 fortified foods or supplements.

Answer 2

Banana provides the following for the body: Vitamin B6, Manganese, Vitamin C, Fibre, Potassium, Biotin and Copper. A full analysis of the nutritional benefits of bananas can be found here: http://www.whfoods.com/genpage.php?tname=foodspice&dbid=7

But, just subsisting on a single food item will eventually lead to death due to organ failures. An adult body needs a wide variety of food types to provide all the energy requirements it needs and no single food item exists that can provide everything for survival. Here is an interesting article that talks about the perils of a single food diet: http://www.livescience.com/18161-food.html

In summary, enjoy the bananas (raw, steamed, fried, cooked) but don't rely only on them.

Answer 3

I use an online tool called Cronometer to analyze diets and specific foods for balance. Cronometer helps to compare nutrient values provided by the USDA Nutrient Database with recommendations from the NIH Dietary Reference Intakes manual.

The screenshot below is what I get when I put 20 bananas (2.7 kg, or 2420 kcal worth) into Cronometer. This assumes a low-to-moderate amount of activity.

Macronutrients

• Total protein is dangerously low. The estimated average requirement (EAR) for a typical adult female is 37 g/day. EAR is defined as likely being adequate for half the population. This banana-only diet provides even less protein than the EAR, so it is going to be insufficient for more than half the female population and nearly all males. This diet will surely result in muscle wasting and eventual organ damage for most people who try it. (Caveat: a highly active person who runs for about two hours every day would need to eat a lot more bananas, and therefore would consume more protein and possibly meet their daily requirement. But 4000 kcal/day is unrealistic for most people.)

Vitamins and Minerals

• Vitamin B12 is absent, but I assume anybody following an all banana diet would be taking a B12 supplement because all vegans should take a B12 supplement.
• Vitamins A and B1 are a bit low.
• Vitamins E and K are very low.
• Calcium is extremely low. Some people suggest that calcium requirements might be lower on a diet with a very low potential renal acid low but I don't have any scholarly sources to support that. This diet would likely cause urine to be highly alkaline which could encourage the formation of kidney stones.
• Selenium may be low, but it depends on trace mineral concentrations in the soil where the bananas were grown.
• Zinc is quite low. Zinc is important to many human health processes.
• Although sodium from food is low, it could easily be provided in an electrolyte solution such as is commonly consumed by athletes.