Episode 105 – Does Eating Breakfast Help With Weight Loss?

Key Topics Covered

Broad Overview of Weight Loss 

  • For weight loss to occur, you have to consume fewer calories than you’re expending.  
  • There is no way in getting around this.  
  • However, in theory, if having breakfast VS not having breakfast was to either directly or indirectly effect either side of that equation is would then either help or hinder weight loss. 
Weight loss person on scale

Assessing the Claim That Breakfast Helps Speed Up Your Metabolism 

  • If taken overly literally to mean increased BMR or RMR, there is no evidence to indicate that. 
  • It is even hard to find research on that, partly since it is so skewed by other variables e.g. changes in calorie intake over time would affect it more than the impact of breakfast vs skipping breakfast.  

Does it increase TDEE through increased incidental movement and/or physical activity?

  • Does someone who eats breakfast end up burning more calories due to having more energy to start the day? 
  • We have some observational evidence for this. Most of that indicates a reduction in physical activity among those that skip breakfast.  
  • But this isn’t exactly proof that skipping breakfast causes that outcome since it is just observational. 
  • And if you are someone who keeps exercise and daily steps extra consistent, this would obviously play very little if any role at all  
  • There are 5 RCTs linked below on this. Three found no significant difference and 2 found that eating breakfast increased physical activity. 
  • So it is a mixed bag.  

 Research Directly Looking at Total Daily Energy Expenditure 

  • The most tightly controlled research on the topic has found no difference in 24hr energy expenditure. 
  • That’s pretty simple and really debunks the claim that breakfast speeds up metabolism. 
  • Exceptions to this could be people who notice a huge difference in their desire to do physical activity of course though. 
  • It’s also worth highlighting that acute studies measuring TDEE over a shorter timeframe than this might be skewed by factors such as TEF, which would increase after breakfast. If calories were matched across the 24hr period though, it would balance out. 

Does Eating Breakfast Reduce Energy Intake Elsewhere? 

  • Theoretically, if you eat breakfast you might be less hungry later in the day. This could lead to fewer calories consumed. 
  • A classic example of this is skipping breakfast, starving in the middle of the day, and then eating more food, usually junk food, than you want in the afternoon or at night.
  • From the opposite perspective, adding breakfast could also simply add additional calories. 
  • In my experience, it can really be different strokes for different folks.
  • Some of my clients are not breakfast eaters and actually like to almost fast in the morning when doing a weight loss phase – and this works great for them.
  • Whilst others may skip breakfast and end up being so ravenous later in the day, that their nutrition plan goes out the window and an excessive intake of energy-dense food takes place – and obviously if that is happening regularly that is going to hinder weight loss.  

Research on This

  • A 2019 systematic review looked at all of the RCTs on breakfast intake and calorie intake
  • They found that people who consumed breakfast ate 260kcal MORE than those who skipped breakfast
  • This indicates a combination of the previous points. Since the breakfasts were larger than 260kcal obviously, they did eat less later than they otherwise would have. But they still added more calories at breakfast than they removed later on. 
  • Once again though, double down on these numbers being averages. They are not reflective of what might happen in your individual case. 
Intermittent Fasting Clock knife and fork

Research on Intermittent Fasting 

  • Technically, research on skipping breakfast does not directly overlap with research on intermittent fasting. 
  • “Skipping breakfast” does not also have a defined timeframe of when to stop eating at the end of the day, in comparison to something like 16:8 fasting which has a defined end time point. 
  • A 2020 systematic review found that ALL 27 randomised controlled trials on intermittent fasting resulted in weight loss on average
  • Once again, this was simply due to a reduction in calorie intake. 
  • In isolation, this looks like a huge win for skipping breakfast. But it’s also worth factoring in other key points like:
    • Is your hunger management throughout the day better or worse when you fast/skip breakfast? 
    • How does skipping breakfast change your behaviours in regard to both food and exercise throughout the day? 
    • What if you have training in the morning? Do you want to do that fasted?  
    • What if you enjoy breakfast and like going out to eat in the morning with friends? Is it worth having fasting/no breakfast as a food rule? 

What does the research show on weight? 

  • That same 2019 systematic review of the RCTs found that there was minimal difference between the two approaches, with a 0.44kg difference trending towards the breakfast eaters weighing more. 
  • This is a pretty clear nail in the coffin for the suggestion that eating breakfast helps weight loss, on average. 
  • That is the RCT research. The observational research has a different story though. 
  • Typically observational research finds that people who consume breakfast have lighter body weights than those who do not. 
  • This doesn’t mean breakfast is the cause of that. For example, we also have research indicating that people who eat breakfast typically have diets that are higher in fibre and micronutrients. 

Other Pros and Cons of Breakfast 

  • Looking beyond just weight, there are a bunch of other things that matter.
  • Breakfast can be an opportunity to get in more of certain micronutrients or types of fibre that might not be consumed at another time in the day – it is often a good opportunity for most people to get some wholegrains, fruit, protein and calcium (dairy or milk alternatives) in.
  • We also have research indicating that protein distribution is a good thing. Adding protein at breakfast could help this + could help satiety. 
  • The quality of the breakfast matters. A high protein, high fibre, micronutrient-rich breakfast is different to one that is the opposite of that.
    • Protein oats with berries & chia seeds is very different to a bowl of fruit loops. 


  • Whether you eat breakfast or not, in isolation, doesn’t really matter. 
  • Calories in vs calories out is what controls weight loss
  • For some people, eating breakfast might make that easier. For others it might do the opposite.  
  • And then there also is the personal preference component. And understanding that it isn’t necessary to have breakfast, or to skip it, can make it easier to achieve your goals with whichever approach you would prefer.  

Relevant Links / Resources

Blog Posts

Studies Mentioned