Fruit breakfast experiment


Hi everyone! I’m very happy to report that the fruit breakfast experiment is now finished. I’ve been eating fruit in different shapes, colours, quantities, and forms as my breakfast for the last 30 days. No coffee, no protein, no bread, no cereals, essentially no <insert anything that’s not fruit here>. 

As mentioned in the initial blog post a month ago the objectives of this experiment were to find out: 

  • How does a fruit breakfast affect chronic fatigue levels?
  • How does a fruit breakfast affect weight?


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In case you don’t feel like reading the 1st blog entry on this experiment let me quickly summarise:

I’m dealing with joint pain, chronic fatigue and inflammation. And not to forget, my eyes are on fire. They burn and feel dry.

Since my trips: GP -> Specialist -> GP -> Specialist -> GP -> you get the idea  for the last couple of years brought me nowhere and I’m not a big fan of chronic pain and feeling weak 24/7 I think I’m a pretty good research subject to validate how different foods and food supplements affect chronic conditions.

I happen to be a scientist from education and I’m going to keep on trying over and over again until I fix whatever causes my problems. Advice that I got from one doctor: “Use eye drops and sip water” helps a bit, but it simply isn’t enough.

The only exercise done in this experiment is walking to and from work, approx. 30 minutes walk one way.

I’m going to share my findings with you here. Enjoy reading!


Red Planet


How does a fruit breakfast affect weight?

Let’s start with this one, cause it’s easier to measure. Long story short: it helps with weight loss. As I count calories and I stay in a caloric deficit I’m going to lose weight anyway, but as fruit is low in calories it helps to reduce overall amount of calories eaten each day.


Fruit breakfast experiment summary table


I’ve lost 3.9kgs (8lb 6oz) in the last 30 days with an average of 1,542 net kcals per day. My fruit breakfast on average had 197 kcals. Would I lose the same amount of weight without the fruit breakfast? If I ate 1,542 net kcals with no fruit most likely I would lose a similar amount of weight, since I would be in a caloric deficit anyway. 



Fruit breakfast experiment weight summary


However, my average breakfast before the experiment was:

  • Shop bought baguette – approx. 600 kcals
  • Medium full fat latte – approx. 200 kcals

That’s approx. 800 kcals for breakfast every day, which is 600 kcals more than the fruit breakfast, quite a big difference in calories. 

Net kcals come from: Food eaten kcals – exercise kcals (walking to/from work) = net kcals. You can see that I had one day with over 6,000 kcals (day 27) – that’s from 2 large pizzas. Yes, I had two large pizzas in one day and it was great. Yet I still lost weight, because the rest of the week wasn’t as calorie full as that one day.


Fruit breakfast experiment net kcals summary


I was experimenting with the amount of fruit for breakfast. My worry was that I would be tired, cause there was no protein and less calories than what I was used to. I was so wrong to worry about it. The only day when I crashed and counted hours for lunch to arrive because of hunger was day 5 (98 kcals breakfast).

I shouldn’t be surprised though – on day 4 (see graph above) I was fasting with only 154 net kcals, so yes no surprise that I was so hungry in the morning of day 5… I didn’t think about it and had a small breakfast of 98 kcals (1 apple + 175g strawberries). So stupid of me, I should have eaten way more that morning.


Fruit breakfast experiment breakfast kcals


What about being hungry? Lack of energy? Read on! 


How does a fruit breakfast affect chronic fatigue and inflammation?

Firstly, let’s not waste time here: joints hurt as they did before, my eyes burn as they did before. No difference observed, not even a placebo effect, but… 


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What a surprise when it comes to fatigue levels. This low-calorie fruit breakfast really made a difference to my energy levels. As you can see in the ‘breakfast kcals’ graph I reduced the amount of  fruit breakfast kcals consumed over time, cause it turned out my body was happy to run on fruit sugar till lunch with no problem.

My stomach wasn’t full. I felt really light walking to work every day, yet my energy level was much higher and I increased my pace too. It really made a difference here.  

At some point I wanted to measure my energy levels on a scale 1-10, but I started doing it at some point in week 3, so I decided that it’s better not to include it here. I will measure it next time. Plenty of experiments to do, so if you have any recommendations what to measure and how, leave a comment below. 



Would I recommend fruit breakfast?  

If you plan to lose weight, or increase your energy levels I’d say definitely give it a go! It is a very simple experiment. Meals are simple too – buy some fruit you enjoy and eat it for breakfast, no prep needed – just wash it!

And of course, if you’re allergic to some fruit then don’t eat it! I wouldn’t want you to get sick! 


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If you’re worried about small meal size blend it using water. The fiber in fruit will give it volume very quickly. It’s not a joke, I would have my blended meal in a beer mug and sometimes it was difficult to finish it. 

I plan to continue eating fruit for breakfast for a long time. Have I mentioned it works better than coffee to wake me up? Well, read on!


Big question: why breakfast?

Fruit is full of sugar, which is great in the morning to kick start your system. At the same time fruit is also full of fiber, which slows down glucose absorption, so it doesn’t affect your blood glucose levels as much as e.g. fruit juice (this one will give you a huge spike in blood sugar, because there’s no fiber to prevent it!). 

I thought I would be tired (no protein, low calories, no coffee), but the opposite was true. I would risk saying that I got a better kick of energy from a fruit breakfast than from a cup of coffee. Could someone explain this to me, please?


Want to see all data?

  • Photos and descriptions of all fruit breakfast meals can be found on Instagram here
  • Fruit breakfast diary on myfitnesspal: username ‘redplanetnutrition’ – see February 4th to March 4th
  • 30 day experiment full table info here (click and zoom in):

Fruit breakfast experiment 30 day data



Try it and let me know how it goes! Would be great to hear from you – leave a comment below!


Dr Bart Baranowski





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