( CNN ) -- Paignton Zoo in Devon , England , is n't monkeying around with their animals ' diets anymore . Zookeepers are trading the monkeys ' favorite fruit in for green leafy vegetables , saying bananas grown for human consumption are full of sugar and calories . `` Wait , even the fruit is n't healthy anymore ? What 's left ? ! ? ! '' CNN reader NeoPrudentist posted in what was soon rated the No . 1 comment on the story . What 's left , indeed . First coffee . Then salmon . Now this ? Not to worry -- this is n't a case of human see , human do . Despite sharing more than 90 % of our DNA with these fuzzy primates , humans have some very distinct differences in anatomy . Those English zookeepers are n't totally wrong . All fruit contains sugar , and bananas are slightly denser calorie-wise than other types of fruit . But when it comes to nutritional bang for your buck , bananas are hard to beat . Just remember -- no monkey business : Eat 'em in moderation . Sugar . Bananas contain about 14 grams of sugar . You may have heard that sugar from fruit is better than the sugar you find in candy . But sugar has the same molecular structure whether it comes from a kiwi or a cupcake . Both contain fructose and glucose , although in varying proportions . Neither kind of sugar is really better or worse for you , experts say ; the body just processes them differently . Fructose is broken down in your liver , while glucose starts to break down in your stomach and needs insulin to be fully metabolized . The good thing about fruit is that the sugar often comes with fiber , which slows digestion and gives the body time to use it as fuel instead of storing it as fat . Speaking of fiber ... Bananas have about 3.1 grams of fiber . Unripe bananas are slightly better for you than ripe bananas , experts say . Greener bananas contain what 's called resistant starch , a type of fiber that your body has trouble absorbing . Studies show resistant starch fills you up and may even help you burn fat . Unripe bananas score 30 out of 100 on the glycemic index ; ripe ones score about 50 . The index indicates how quickly a carbohydrate increases your blood sugar levels . Low-GI foods may help you lose weight because they help control appetite and delay hunger , according to the University of Sydney . Power boost ! Every long-distance runner knows the power of a good banana . The fruit contains high levels of potassium and magnesium -- two nutrients athletes lose when they sweat . Bananas also have a chemical property that may help control stomach pain and reduce your risk of diarrhea or constipation , according to LiveStrong.com . That 's not all . One banana offers about 25 % of your daily need for vitamin B6 . B6 is important for about 100 different metabolic enzyme reactions , according to the National Institutes for Health , and is involved in brain development during pregnancy and infancy .
A medium-sized banana has about 105 calories and only 0.5 grams of fat . Bananas do contain 14 grams of sugar , but that comes with a healthy dose of fiber . Bananas also offer potassium , magnesium and vitamin B6 .