Does Training On An Empty Stomach Help You Lose Weight?

It’s a perennial question (and sometimes a perineal one).

If, broadly speaking, consuming too many calories and not burning them off leads to increased body fat storage, surely training without taking in any calories is going to tip the scales in your favour?

I’ve been asked about the subject of ride nutrition in the past. I didn’t know much then. I don’t know a great deal more now. But I’m eager to explore. Let’s take a look.

Food As Fuel

The basic presumption when it comes to eating and exercise, is that you should try to be fully fuelled for a session.

There are certainly types of training, and shorter session lengths, where you won’t want or need to take on fuel. For everything else, the starting point is to assume that you’ll need to eat (or drink) calories before, during or after the session (and sometimes all three).

Overcompensation Not Overconsumption

It’s generally accepted that you don’t increase fitness whilst training. During the session you placing stress on your aerobic system and your muscles. The increase in fitness takes place after the training ‘dose’ (as Friel puts it), when your body (hopefully) rebuilds itself to be stronger than it was before (known as ‘overcompensation’).

There is a growing body of evidence that the most effective way to build fitness is to undertake a programme made up of some high intensity sessions along with a reasonable volume of low intensity training.

The trick is to make the high intensity sessions really count. A key component of doing that is to make sure you have sufficient fuel to carry out the session.

The danger when trying simultaneously to reduce your calorie intake for weight loss, is that your ‘high intensity’ session becomes a shortened, moderate intensity ride because you bonked half way round.

You Don’t (Often) See A Fat Pro Cyclist

In my unscientific opinion, the best way (for an aspiring cyclist) to achieve a long term reduction in fat is to achieve and maintain a good level of fitness on the bike.

Everything is easier when you feel fit. You stack the cards in your favour.

Your general motivation to undertake physical activity tends to be higher. You feel better squeezing into revealing lycra.

The canon of potential climbs to conquer increases in line with your confidence and ability. You can ride further, exploring new routes and challenges. The local club ride becomes a possibility rather than an embarrassing abort-after–5-minutes affair.

How the fitness virtuous circle manifests itself will differ from rider to rider, but my point is that improving your fitness level should be your main priority, even if you really want to shed some pounds.

All of which is a long way of saying that decisions over the fuelling for individual training sessions should be made to prioritise long term fitness gain over short term (potential) weight loss.

You’ll thank me in the long run (as if I’ve got anything to do with it…)

Winning The Battle But Losing The War

It’s not even certain that starving yourself when training does result in short term fat loss. In fact, there is evidence of quite the opposite.

According to Matt Fitzgerald in his excellent book, Racing Weight: How to Get Lean for Peak Performance, studies have shown that athletes who do not eat sufficient food whilst training have a greater tendency to overeat in the hours following the session.

In the study cited above, the total number of calories consumed over an exercise day by a participant was lower when the participant took on fuel (gels, sports drink, pork pies) during the exercise itself, versus training with water only.

Racing Weight: How to Get Lean for Peak Performance

My favourite book on how to get lean (and look good-ish) *and* perform strongly on the bike. Full of clear, actionable advice.

Check price
If you click this link and make a purchase, I earn a commission at no additional cost to you.

Sample Size of One (Which Is Me)

I know from personal experience that in cases where I haven’t eaten following a good ride, I have a tendency to:

(i) choose less healthy food options for a meal later that day (“I’ve earnt it…”); and

(ii) give myself a larger portion of food at the next meal (my ability to deal with temptation is reduced).

Fitzgerald notes that the converse is true for athletes that are well fuelled during the session, or, for a shorter ride, eat a sensible post-ride snack. These athletes tend not to overeat in the hours that follow.

In short, if you are going to err on the side of fewer calories consumed during training sessions, be aware that you may need to work harder (in terms of resolve) to make sure you don’t replace those calories (and more) over the remainder of the day.

Rule 5 (Not The Velominati One)

(Which is a sub-heading that might not mean much to you – if not, here is the other rule 5).

As long time readers of this blog will know, the aforementioned ‘Racing Weight’ is my favourite book on losing weight / getting lean / eating for performance. It’s based on a few (sensible) rules.

Fuelling during a training session is ‘Rule 5’ (the ‘rule’ being ‘you should’).

Rule 5 (energy) gels with Rule 4, Eat Before Exercise, which:

  • enhances workout performance (i.e. get more fitter, get less fatter);
  • promotes calories burned versus calories stored (as fat)

and Rule 6, Eat After Exercise:

  • if you’re going to eat eventually (we assume you are), now is the time to do it. Your tired muscles are crying out for chemical shizzle with which to rebuild themselves and replace stored glycogen. In the period after exercise, the body will shunt calories, that might otherwise be stored as fat, to your muscles;
  • double bonus – eating promotes recovery, the quicker you recover, the quicker your performance improves, the quicker you can put in another hard workout. Bish bash bosh.

(In dealing with Rule 6, I might have, er, paraphrased Fitzgerald somewhat. If you’re interested in learning more about the first bullet point, which is known as Energy Partitioning, I found this TrainingPeaks article useful – though note that it’s guest written by a nutrition company…).

BUT(T) – It All Depends On What Exercise You’re Doing

Remember the central Racing Weight concept (which we’ve co-opted here at the Church Of The Sportive Cyclist):

Eating that promotes athletic endurance performance is the best way to get lean.

Fuelling during a ride is only beneficial for an intense or a long workout session. You shouldn’t need to eat for an easy or moderate workout of less than 2 hours, or for an intense session of less than 1 hour.

For eating before and after the session, there is not the same prohibition for short or easy rides. But use this ride length/intensity framework to temper the types and amounts of food you eat.

For a recovery ride, you do not eat to be jacked up on carbs and caffeine prior to leaving the house. A large curry consumed upon completion will do more harm in terms of fat storage than it will benefit your future performance by promoting the repair of those barely stressed leg muscles.

What To Eat Whilst Riding

This could be a post all by itself (and I’d guess there are about a million such posts, if you want to search for them).

Risking the ire of the vast sports nutrition industry, I’d say that what you eat (or drink, since we’re talking sports drinks as well) whilst riding is relatively unimportant (within certain limits).

To be clear, that post-ride curry shouldn’t be an intra-ride one either. Scotch eggs, questionable (can you smell gas?).

But the most important thing is to find something (or a few somethings) that provides energy, that you find appetising (or at least get-downable) and that doesn’t cause you discomfort in t’ guts.

Two observations from the pro peloton:

  1. It’s not uncommon to see riders eating jam sandwiches (on white bread shock horror) and drinking cans of coke.
  2. Pro riders (despite everything: radios, experience, nutritional advisers) still get it wrong on the bike, bonking, forgetting to eat.

This tendency towards the latter means that pro teams accept the former.

Better to maximise your chances of consuming something, than to obsess other the nutritional content of a super fuel that the rider can’t, or won’t, get down their gullet.

Sweets For My Sweet

Clearly the risk of losing interest in food is greater for longer, more tiring rides, where your appetite for yet another sickly sweet sports drink or gel starts to wane.

But you still have some leeway on shorter rides to eat what, at other non-exercise times, might be described as junk.

Specially formulated sports drinks are not vital to optimal performance (well, they might be, but I’m in no danger of achieving an optimal performance, whatever I fuel with). Something high in sugar and potentially with a little salt will do just fine.

I’ve quite happily ridden (and not bonked) whilst fuelled by Jelly Babies (which do have a little salt in each one), Haribo, bananas. And crisps (one of the options offered at RideLondon, presumably for commercial reasons).

Oh yes, and cake. Hell, what’s the point of a long ride if it doesn’t include a coffee and cake stop…?

Sugar For My Honey

If I was slightly more scientific in my writing, I’d mention that the boffins reckon that, at most, 60g of carbohydrates can be consumed each hour. There’s no point in consuming any more (assuming you can stomach it).

Depending on the brand, that 60g corresponds to between one and three energy gel sachets. Suddenly that jam sandwich doesn’t sound too bad after all…


Not eating whilst training, in order to lose weight, runs the risk of doing the opposite.

Eat for performance first. Your body composition will follow.

As to what to eat, I’m sure I’ll come back to the topic in future posts.

For now though, a delve into the Sportive Cyclist archives throws up a post I wrote ahead of my first 100 mile sportive (aka RideLondon 2013).

It’s a little OTT, but may contain the odd grain of wisdom.

Until next time, safe cycling.

Monty - Sportive Cyclist
Monty is an enthusiastic road cyclist with only moderate talent. He started Sportive Cyclist in 2013 to record the journey to his first 100 mile ride, the RideLondon 100. Over time the blog has expanded to include training advice, gear reviews and road cycling tales, all from the perspective of a not-very-fit MAMIL. Since you're here, Monty would also like you to check out his YouTube channel. Also, Monty really needs to stop referring to himself in the third person.

5 thoughts on “Does Training On An Empty Stomach Help You Lose Weight?”

  1. Hi Monty,
    Interesting topic and sound advice all round.

    As a bit of an old geezer (65) I’ve found that the fuelling regime has had to alter a bit as the years tick inexorably by (I’m now SIX pages down on those ‘what year were you born’ forms on internet sites!).
    I find I have to be really disciplined about taking on fuel and fluids little and often, even on quite modest 1 -2 hour sessions.
    I’m rigorous about eating half an energy bar every 30 minutes and a good swig of fluid every 15 minutes and I do this from the ‘get go’ on every ride.
    I suppose it’s about loss of muscle mass as you get older? I’m sure someone clever will tell me.

    Be interested to know of any thoughts from other ‘mature’ riders.

    • Thanks Kel. Interesting comment. I can’t recall this particular point being mentioned in that Friel book I reviewed recently.

      Have others noticed the same thing?

      • I’m with you, Kel. At 56 years and 117 Kg, if I don’t consume about 250 calories every 45-50 minutes I will bonk at 80-90 minutes seemingly without regard to the intensity of my ride. I tend to eat it all at once or over 15 minutes, though.

        Not sure about losing muscle mass as we age being inevitable, though. In the last year, since returning to cycling I have lost a significant amount around the middle but only a couple of Kg overall. We can build muscle even at relatively advanced ages. Much of this was thanks to Monty mentioning the Sufferfest videos in a trainer review. Kudos, Monty. I ordered the Friel book at your recommendation, too.

        Thinking as I type (dangerous), I realize that as my leg muscle mass has increased, so has my ability to go hard for an hour without anything more than a few swigs of a sports drink. I still feel lousy at an hour if I am just taking on water. But, I drink far less than I did at the beginning og my return to fitness. Maybe the need for regular feeding is related to the size of the glycogen tank.

  2. Good information Andrew……a couple of queries:

    – is this 60g of carbs an hour only really appropriate for when you are racing? I’ve just been out today for a 60 mile ride and didn’t take on anything like 60g and felt fine, however, I wasn’t racing, rather just out for a nice ride with a friend.

    – also if you are out for say a 4 hour ride at what point should you start taking on the 60g of carb, straight away, after the first hour etc? I read somewhere that 15 mins after you start and every 15mins thereafter, don’t know if thats right



    • Hi Mike,

      I understand the 60g an hour figure to be the maximum amount of carbs that the body can transform into fuel for use in the muscles. The actual figure will differ from person to person.

      It’s not how much you *should* eat per hour. That will depend on how hard you’re going, and for how long overall.

      If you’re taking things very easily, you’ll be using more fat as fuel and the glycogen stored within your muscles won’t be used up as quickly.

      As to when you start fuelling, again it will depend on the nature of the ride (really, the intensity). If you’re immediately starting to run down your glycogen stores (because you’re going hard), you’d want to start earlier rather than later. It’s very hard to catch up if you find yourself running low, hence why the advice is to start early, consuming little and often.

      Fuelling tends to be quite a personal thing. Whatever works for you. Just perhaps not the brandy and amphetamines that did for Tommy Simpson…


Leave a comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.