Are Bananas Good for Weight Loss?

Bananas contain fiber and resistant starch, which support weight loss. They're also a nutritious, low-energy-density food, which is good for dropping pounds. And they don't live up to their once bad reputation of being a diet-wrecking fruit to avoid.

But when it comes to a banana diet, results really depend on calories. You should set your daily calorie goal to ensure healthy weight loss and must include the calories from bananas as part of your total daily intake.

With their moderate calorie count, you may wonder if a banana for weight loss is a good way to go. But the fruit can work well within any diet plan, but you first need a daily calorie goal. If you're unsure how many calories you consume, keep track of everything you eat and drink for a few days and tally the total calories.

The best way to lose weight and keep it off is to drop just 1 to 2 pounds a week, reports the Centers for Disease Control and Prevention. To determine a calorie goal that achieves weight loss at that rate, reduce your daily caloric intake by 500 to 1,000 calories. Now you can plan to work bananas into your menu.

A large, 8-inch banana has 121 calories, but if you choose a small, 6-inch banana, you'll shave off a quarter of the calories as it only has 90. A banana supplies the perfect number of calories for a snack, but also has enough calories to ruin a diet if you meet your daily calorie goal, and then randomly add the banana.

While bananas provide a range of nutrients, they are excellent sources of potassium and vitamin B6 and have around 10 percent of the RDA for a nutrient you might not expect — vitamin C.

​Read more:​ Top 10 Health Benefits of Bananas

The resistant starch and fiber that bananas contain not only support weight loss, but also aid in digestive health. A large banana has about 4 grams of dietary fiber, which makes it a good source based on the recommended intake established by the Institute of Medicine: 25 grams daily for women and 38 grams for men.

Fiber plays an important role in weight loss because it slows digestion, which helps you feel full and keeps blood sugar balanced. Avoiding spikes in blood sugar makes it more likely that your body will burn fat for energy, according to an article in the​ Journal of Nutrition​.

Most starch in food is a complex carbohydrate that provides glucose for energy, but some foods contain a different type of carb called resistant starch. Resistant starch is incompletely digested and is instead, fermented in the colon. Fewer calories are produced for each gram of resistant starch than for each gram of other carbohydrates. Green bananas are one of the top sources, and the amount goes down as they ripen.

Studies suggest that resistant starch may stimulate the breakdown of stored fat, but more research is needed to prove its effectiveness, according to a January 2015 review published in ​Critical Reviews in Food Science and Nutrition​. At the very least, eating a green banana instead of the same size ripe banana means you probably absorb fewer calories because the green one has more resistant starch.

​Read more:​ What is the Function of Starch?

For many years, bananas had the reputation of being bad for weight loss because they had more carbohydrates than other fruits. It's true that most fruits have fewer carbs, but a large apple has about the same number as a large banana.

The carbs in bananas also range from 23 grams in a small banana to 31 grams in a large banana. And remember that some of the carbs in a banana are resistant starch, which other fruits don't contain. Beyond the number of carbs, the important factor is the impact they have on blood sugar.

Carbs consisting of simple sugar without fiber or starch cause an increase in blood sugar, which is bad for weight loss for two reasons: First, if you don't need the sugar for energy, it's stored as fat. Additionally, the insulin that's released when blood sugar spikes sends signals that stop fat already in storage from breaking down. The glycemic index rating indicates the effect of carbs on blood sugar.

The glycemic score of bananas depends on how ripe they are, but on average, they have a score of around 50, according to a December 2008 review in ​Diabetes Care​. This keeps them in the low-glycemic range, meaning they have a small impact. However, it's close to the moderate range, which begins at 56.

Energy density is a term used to describe the number of calories per gram of food, reports the Centers for Disease Control and Prevention. Low-energy-density foods provide more food with fewer calories, primarily because they have extra bulk from calorie-free water and fiber.

The benefit of low-energy-dense foods is that you can eat more food while keeping calories down, promoting weight loss. It also means that you don't have to feel hungry while you're dieting.

In addition to their fiber content, bananas are 75 percent water, which makes them a fairly low-energy-dense food. As you might guess, most fresh fruits and vegetables work well in a weight loss diet because they're low in energy density.