Having Breakfast Before or After Training

Carlos Sánchez 7 min. of reading Fitness Leave a comment

Have you ever considered what the real differences are between having breakfast before or after training? Is it better in terms of health and performance to go to the gym on a full or empty stomach?

Benefits of having breakfast before training

We can’t universalise the advantages of having breakfast before training, because as always, many athletes are better off going out to train on an empty stomach, especially if those workouts are performed at very early hours.

Nevertheless, depending on what your sport is, it may be a good idea to have breakfast before training.

In the field of strength sports

Where we could include indoor strength/hypertrophy work, weightlifting, powerlifting, or mixed modalities such as high-intensity functional training, it is good to start with full muscle and liver glycogen stores.

Can you train on an empty stomach?

This will get:

Better sports performance (more repetitions and sets, higher loads, WODs in less time…).
Lower risk of injury.
Better muscle recovery.
More anabolic hormonal environment.

After a night’s sleep, muscle deposits aren’t too affected (as we’ve been at rest), but liver glycogen deposits will normally be less than 50% of their capacity, because on an empty stomach the liver uses liver glycogen to maintain stable glycemic levels (glycogenolysis).

So having breakfast before training will maximise those liver glycogen deposits, achieving the aforementioned effects.

In the field of endurance sports

Where we could include running, cycling or swimming, I would point out at least two different situations:

Sessions of under 90 minutes.

In this case, many athletes prefer to train on an empty stomach, and see their performance improved when they do.

If it is the case for you, there’s no reason why you shouldn’t have your first intake of food before the session, except for special situations (pathologies).

In any case, we emphasise that this is a matter of preference and that there is no one answer that is clearly superior to the other.

Sessions of more than 90 minutes.

When sessions extend beyond the hour and a half it is unwise to go out without breakfast, or not have anything during the event or training session (intra-training).

For such prolonged efforts, and especially when the intensity is moderate-high, sports performance and the risk of injury will be increased.

This general recommendation isn’t for individuals highly adapted to fasting training and with very high metabolic flexibility (Killian Jornet wouldn’t fall into this category, for example).

And what are the benefits of having breakfast afterwards?

Training on a fast has gained popularity in parallel with the rise of intermittent fasting.

Something that not so long ago was considered an “unwise” practice, even detrimental to health, now seems to be the new holy grail of sports performance.

As always, reality is much more relative and context-dependent.

Training on a fast has been studied as a way to improve metabolic flexibility and even as a strategy in competitive athletes to improve performance (a strategy called “train low, compete high”).

So far, the science has been able to corroborate that, yes, this practice enhances some physiological adaptations at the mitochondrial level and in the metabolism of fats, but that when compared with usual practice, does not demonstrate better results in sporting terms.

So, why would a person rather train on an empty stomach than eat a good bowl of oats and fruit before training?

Well the only compelling reason is personal preferences and the context of each person:

Many endurance athletes can’t tolerate, especially at the digestive level, eating breakfast just before starting a training session.

In this case, either we space out the breakfast before training, or we choose to have breakfast afterwards.

Some people can’t tolerate breakfast before training, but they do feel better when training on a fast.

This is partially due to the “fasting” hormonal environment, the increase in cortisol and catecholamines, and the predominance of the sympathetic nervous system.

During our time as hunter-gatherers we always “trained” while fasting, as it was the only way to find food.

Our physiology, with some prior preparation, is perfectly adapted to sustain physical effort in a pre-prandial situation.

When is it best to have breakfast?

If you are going to have breakfast before training, it’s not a good idea to do it immediately before, as the process of absorption and digestion will interfere with the training.

Have you seen people vomiting in the gym or in the box?

This is down to two factors: recent ingestion + high intensity.

The stress factor derived from high intensity training stimulates colonic motility and decreases gastric motility.

This is why you may have ended up looking for the nearest toilet at peaks of intensity.

An intake close to an intense workout is the perfect recipe to end up vomiting what you’ve eaten and feeling really bad.

How much time should you take between breakfast and physical training?

As a general rule, if your breakfast is a standard breakfast, let at least 60 minutes pass from when you finish breakfast until you start training.

If you need to ingest more carbohydrates because it is required by the test or specific training, it’s better to eat 90 to 120 minutes before starting training.

And if you are someone who has to ingest very large amounts of carbohydrates before the test (ultras, marathons, etc.), you may even need to eat 3 hours before starting (as long as the schedules allow it).

What to eat for maximum performance?

Some practical recommendations are as follows:

Avoid just before sporting events

Fibre takes longer to digest, so it can cause digestive problems if you ingest it at short notice of the event or workout.

This is especially true in people with digestive problems.

The norm would be: the closer to training breakfast os, the less fibre you should eat.

Decreases fat intake

By the same token, fat slows gastric emptying, so if you eat a breakfast rich in fat (bacon, egg yolk, avocado…), along with your carbohydrates, these may still be undigested when you need to be performing.

Similarly to the previous point, if there is sufficient time between breakfast and physical exercise, there would be no problem in including fat in the diet.