Will fruit make me fat?

  • By Brian Keane

Depending on who you talk to, the answers can range from ‘fruit will make you fat’ to ‘we’re evolved to eat fruit, you should only eat fruit!’ so whats the answer? Is fruit going to support you in a healthier, fitter, leaner you or is the thing thats been holding you back in getting in the shape you’ve always wanted? Firstly, its important to understand how fruit (fructose) and carbohydrates actually work within you body.


The human body is designed to run on carbohydrates. While we can use protein and fat for energy, the easiest fuel is carbohydrate.

When we eat complex carbohydrates like whole grains, vegetables, beans or lentils, or simpler carbohydrates like fruit, the body does exactly what it is designed to do. It largely understands what these foods are and thus breaks them down pretty effectively for energy.

Even better, as these foods haven’t been modified or processed, all the nutrients that the body needs for digestion and metabolism are already present in these whole foods. They also contain for fibre (which is a less digestible type of carbohydrate), which helps the digestive system run smoothly.

Carbohydrates have got a pretty bad reputation over recent years but when used correctly, they can be massively beneficial in keeping blood sugar stable, keeping energy levels constant and fuelling your body for workouts.

Remember, carbohydrates have one job- to give you energy; there is no ‘essential carbohydrate’ like essential amino acids from protein or essential fatty acids from fat; they exist to give your body and brain energy.

With this in mind, using them correctly can be a great tool in your arsenal. I like to think of carbohydrates like a guard dog, if you treat them well throughout their life, they will look after you and help you sleep better at night. If you abuse them though, they can turn around and bite you just as fast. So that begs the question, where does fruit fit into this?


Depending on who you talk to, the answers can range from ‘fruit will make you fat’ to ‘we’re evolved to eat fruit, you should only eat fruit!’ There are few topics where I can argue just as strongly on both sides.

On one hand, I am a massive fan of the vitamins and minerals that fruit contains, also if timed right, it can balance blood sugars and enormously curb a natural sweet tooth. On the other hand, fructose is converted to glucose pretty easily and excess can lead to unnecessary fat gain.

Also there are certain fruits that are nearly pure glucose and can hugely elevate blood sugars leading to a whole host of hormonal, energy and weight gaining problems. This leads me to believe that the truth isn’t whether fruits are inherently good or bad, it’s the selection choices you make and their timings that are key.

Fruit contain a simple sugar called fructose, which needs no digesting and can therefore enter the bloodstream quickly, like glucose or sucrose. However, unlike them it is classified as slow releasing because the body cannot use fructose as it is and has to convert it to glucose before you body can effectively use it. This slows down the sugars effect on the metabolism.

Some fruits such as grapes and dates contain pure glucose and are therefore faster releasing. Bananas contain both and there raise blood sugar levels quite speedily (although green bananas are better than yellow for this).

In my opinion, the negatives of raising blood dramatically (even post workout) massively outweigh the benefits so I would avoid these foods or keep them very moderate to avoid in imbalance in blood sugars or hormones, which can lead to unnecessary energy drops or hormonal imbalances.


The key is choosing good sources of fruit (apples, pineapple and blueberries to name a few) that are loaded with vitamins, minerals and antioxidants and fitting them into your overall nutritional plan. The simple answer is excess (way too much) fruit will probably slow down your fat loss goals so if you’re eating 5 or 6 pieces every day and can’t figure out why you are not losing weight, try dropping it to 1 or 2 pieces until you hit your fitness goal and then re-introduce it back. Also if you are spiking insulin levels regularly with normal bananas, grapes or dates; then that probably isn’t supporting you either so I would suggest limiting or substantially cutting back on these sources until you’ve hit your fitness goals. I hope that helps, Now I’m off to have a protein fruit smoothie 😀

Brian Keane Fitness Podcast

Brian is a qualified personal trainer, sports nutritionist and strength and conditioning coach.

He is the best selling author of the book The Fitness Mindset and currently travels the world as a professional speaker. He also hosts the #1 podcast The Brian Keane Podcast.

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