Does eating breakfast really kickstart your metabolism?

November 17, 2020

We’re often told that breakfast is the most important meal of the day. 

Since the invention of the first processed breakfast foods in the late 1890s, we’ve been bombarded with marketing campaigns touting the importance of breakfast for starting your day right. 

But skipping breakfast is becoming increasingly popular, with supporters claiming that delaying eating until later in the day and spending more time in a fasted state can reduce inflammation, improve insulin sensitivity, and aid weight loss. 

So should you eat breakfast? The results of our PREDICT studies suggest the answer is: it depends on your unique biology. 

Here’s why.

Nutritional guidelines promote eating breakfast, but are they based on solid science?

Nutritional guidelines worldwide state that breakfast is an essential part of a healthy lifestyle, helping to kickstart your metabolism, provide mental clarity, and stop you from getting hungry later in the day.

These guidelines are based on observational studies showing that people who frequently skip breakfast are more likely to be obese and have associated conditions like heart disease and diabetes. But recently, scientists have begun questioning the benefits of breakfast. 

The truth is that many of these observational studies that link skipping breakfast with weight gain and poor health fail to adjust for other factors like education, poverty and overall diet.

So while these kinds of studies suggest that breakfast eaters might be healthier, that doesn’t mean eating breakfast guarantees optimal health. 

Controlled trials are calling the benefits of breakfast into question 

Over the past few years, scientists have tried to eliminate these confounding factors by conducting randomized controlled trials, which specifically ask people to eat or skip breakfast and then measure the results. 

A review of all the randomized controlled trials that have studied the effect of breakfast on weight and energy intake so far was published in the British Medical Journal in 2019. 

This review called into question the idea that breakfast kick starts your metabolism and aids weight loss, with most of the research showing little difference in average weight loss between those who do and don’t eat breakfast. 

In fact, they found that, on average, people who skipped breakfast consumed 260 calories less than people who ate first thing in the morning, casting doubt on the belief that a good breakfast helps you eat less throughout the course of the day. 

However, the review also highlighted that many breakfast studies were at high risk of bias, and that there were huge inconsistencies in the results between trials. 

These inconsistencies may be because the studies looked at the average response to breakfast. This overlooks the fact that we are all unique, and we all have different responses to food. 

There’s no “one-size-fits-all” rule for whether you should eat breakfast 

A recent study called TREAT, which looked at the effects of meal timing and fasting on weight loss, showed that the impact of not eating before midday varied widely between individuals. 

For some people, missing breakfast contributed to weight loss. But for others it had the opposite effect.

Interestingly, results from our PREDICT study showed that your blood sugar and fat responses after eating lunch heavily depend on the foods that an individual chose to eat for breakfast, showing that what you eat is important as when you eat. 

This effect also varied widely between individuals, emphasizing the fact that there really is no one-size-fits-all approach to eating.

So is your breakfast routine setting you up for the day or storing up hunger for later? The answer depends on your unique biology. 

Our ZOE test kit contains everything you need to measure your responses to food, understand your unique metabolism, and get personalized recommendations of the foods that fit your body best.

The big facts on breakfast 

  • Historically, observational studies have linked skipping breakfast with obesity and poor health, but these studies failed to adjust for other factors that influence eating patterns and health.
  • Randomized, controlled trials can tell us more about the impacts of breakfast, but the evidence so far is conflicting.
  • Recent studies show that skipping breakfast may help some people lose weight, but it doesn’t work for everyone.
  • Whether you should eat breakfast or skip it - and which foods you should choose - depends on your unique biology. 

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