Eat More and Lose Weight: What 9 Months of Fuelling Changed

 Yes, a triathlete can eat more and lose weight, but only if they were underfuelled to begin with. Curt, a 54 year old age grouper, went from around 2,000 calories (about 8,400kJ) a day to closer to 3,000 (about 12,500kJ), lost 8kg over 9 months and stopped bonking, all while training harder and recovering faster. Eating enough to cover training lets the body drop out of a chronic stress state, protects muscle and finally lets go of stored body fat. Slow, steady loss of around 0.5kg a week is the target that keeps you strong.

Nine months ago I put three brand new Triathlon Nutrition Academy athletes on the podcast a few weeks after they joined. Curt is a 54 year old scientist from Texas. Jade is a 39 year old health and PE teacher and mum of three in Western Australia. Steve is 71, from San Diego, with more than 300 races in a 30 year triathlon career and no formal nutrition education until now.

They have now finished all three phases of the program, so I brought them back to find out what actually changed. The answer surprised even me, because a fair chunk of it had nothing to do with swim, bike or run.

If you are a busy age grouper trying to fuel 10 to 15 hours of training a week around work and family, this is what learning the fourth leg properly looks like in real life.

Can You Really Eat More and Lose Weight as a Triathlete?

Curt came to me eating around 2,000 calories a day, or less, because he was trying to diet. He bonked every couple of hours, got hangry enough that his wife had had enough and needed a nap after every big session. He was training hard and going backwards.

He now eats closer to 3,000 calories a day. He has lost 8kg (nearly a pound a week, as he puts it), he is stronger in training and in races and he recovers faster. His only other change was a daily dog walk. He did not believe me when I first laid out what he should be eating (fair enough).

This works because Curt was significantly underfuelled. When you hold a large energy deficit (the gap between what you burn and what you eat) for months on top of a big training load, the body treats it as a threat. Stress hormones stay high, training quality drops because the tank is empty, recovery slows and the body hangs on to body fat because it has no reason to believe more food is coming.

The 2023 International Olympic Committee consensus statement describes exactly this pattern. Relative Energy Deficiency in Sport (REDs) is a syndrome of harmful health and performance outcomes in athletes exposed to low energy availability, and it affects male athletes just as much as female athletes (Mountjoy et al., 2023, British Journal of Sports Medicine). Curt was not lazy and he was not doing it wrong on purpose. He was doing the thing every triathlete thinks they have to do.

If you are eating less to lose weight and still bonking, still napping after sessions and still not shifting body fat, then you are almost certainly underfuelled, and the fix is more food at the right times, not less.

How Much Weight Should a Triathlete Lose Per Week?

Slowly. A study on elite athletes compared losing 0.7% of body weight per week with losing 1.4% per week. The slow group actually gained 2.1% lean body mass and improved their strength while dropping fat. The fast group did not (Garthe et al., 2011, International Journal of Sport Nutrition and Exercise Metabolism).

For an 80kg triathlete, 0.7% is about 560g a week. Curt’s 8kg over 9 months averages out at around 200g a week, well inside that safe range, and it is why he got faster while getting lighter rather than losing power along with the weight. I covered how to protect your power while dropping body fat in Episode 230, How to Lose Weight Without Losing Power, and the muscle side of the equation in Episode 260, How to Gain Muscle While Losing Body Fat.

If you are losing more than about 1% of your body weight a week during a training block, then you are losing muscle and performance with it. Slow it down.

What Does a Fuelled Training Day Look Like?

Curt’s day now runs on a simple structure. He never trains fasted, so every session has a pre workout meal. Every session has a recovery meal with a protein and carbohydrate target attached. On a hard day he tops up his carbohydrate to refill his glycogen (the stored form of carbohydrate in your muscles and liver). If tomorrow is the hard day, he eats a little more today. Normal days are pre workout, post workout, lunch, a healthy snack and dinner.

Two things make this stick. It is adaptable, so a missed meal is a lesson rather than a failure. And it is not punitive, which matters for a sport full of high achievers who spiral the moment something is not perfect.

Jade’s change was different again. She spent years training fasted because she was worried about how food would sit in her stomach, and she was skipping strength sessions because the macro timing felt too hard to work out. Every session is now fuelled before, during and after, with recovery straight away rather than 2 or 3 hours later. In her second Ironman build she has pushed her bike fuelling to 90g of carbohydrate an hour, which is the intake the research supports for events over about 2.5 hours, as long as it comes from multiple transportable carbohydrates (a mix of glucose and fructose) and you train your gut to handle it (Jeukendrup, 2014, Sports Medicine). On the Friday she said no way. By Saturday she was doing it.

If you are training fasted because you are scared of gut upset, then start with small, practised amounts of carbohydrate in training and build up. Your gut is trainable and your energy on the run depends on it.

What Changes on Race Day When Your Nutrition Is Sorted?

Steve has raced more than 300 times. For 30 years he hand waved the nutrition part, followed whatever his mates were doing and treated multisport nationals (5 national championship races in 3 days) as a suffer fest to be survived and then drowned at the pub. This year we built a race week plan in Power Hour. He felt good through all 5 races, with no lag in energy, and he now describes nutrition as free speed for one main reason: doubt is an anchor, and removing it lets you focus on the swim, bike and run.

Curt’s plan now starts 1 to 2 days before the race instead of one meal before. His fluid and his fuel are separated, so on a cold day he does not have to drink a bucket of liquid to get his carbohydrate in. He still watches other athletes in transition deciding whether to put two scoops in the bottle instead of one and it does his head in. Never try anything new on race day.

Jade’s race plan for Ironman Western Australia was written months out this time. Last year she sat down the night before with a scribbled bit of paper, working out sodium and carbs per hour by hand. This year the mental load is gone and the goal is sub 13 hours.

If your race nutrition plan is being written the night before, then it is not a plan, it is a guess. Write it weeks out, test it in your long sessions and adjust.

What Changed Outside Triathlon?

This is the part I did not script. Curt’s relationship with his wife improved because he is no longer hangry all the time. She walked into the kitchen, saw spinach going on his eggs and asked who he was and where her husband had gone. He has also gained at least an hour a day because he no longer needs a nap after every session.

Steve has the energy to get back to the beach, which he had let slide from 6 days a week to a couple of days a month. He has 7 grandchildren and a strength program that is finally supported by the right protein at the right time, to the point that blokes in his age group are asking what he has been doing. At 71, his weight has not changed, but his body composition has.

Jade’s whole family is on board. Smoothie bags in the freezer, the pressure cooker and slow cooker doing double batches, and her son making her recovery breakfast and carrying her fuel on long runs. Her kids now talk about having energy in the bank for their own sport.

None of that is on a results spreadsheet, and all of it is why I do this job.

Frequently Asked Questions

Q: Can I eat more and loose weight while training for a triathlon?

A: Yes, if you are currently underfuelled. Eating enough to cover your training load lowers the stress response, protects muscle and lets your body release stored fat. Curt added around 1,000 calories a day and lost 8kg over 9 months.

Q: How many calories should a triathlete eat to loose weight?

A: There is no single number, because it depends on your body size, training load and goals. The reliable rule is a small deficit that produces around 0.5 to 0.7% of body weight lost per week, which for an 80kg athlete is roughly 400 to 560g a week. Faster than that and you lose muscle and power.

Q: Should I train fasted to loose body fat?

A: No. Fasted training reduces the quality of the session, increases the chance of bonking and makes recovery harder. Fuel before, during and after your key sessions, and manage body fat through the overall day rather than starving the workout.

Q: How much carbohydrate per hour should I take on the bike in an Ironman?

A: For events over about 2.5 hours, research supports up to around 90g of carbohydrate an hour from a mix of glucose and fructose sources, provided you have trained your gut to tolerate it. Build up gradually in training rather than jumping straight to 90g on race day.

Q: Why do I need a nap after every long training session?

A: Persistent post-session fatigue is usually a sign that you are not fuelling the session or recovering properly afterwards. A recovery meal with carbohydrate to refuel and protein to repair, eaten soon after finishing, removes most of that crash.

The Final Word

You cannot grit your way through triathlon training on an empty tank, and you cannot starve your way to race weight while asking your body to perform. Curt, Jade and Steve are three different athletes in three different decades of life, and the same thing changed for all of them: they stopped guessing and learnt how to fuel for the work required.

Nutrition is not something you fix in a week, and it is not something you fix for life by collecting free nuggets from AI, YouTube or podcasts. You learn it, you practise it and you make it your own. If any of this sounds like you, do not stress, because it is a very fixable problem with the right education.

That is exactly what the Triathlon Nutrition Academy is built for: 9 months learning how to fuel your body for your own training, with me and a group of triathletes like Curt, Jade and Steve beside you. Find out more about the Triathlon Nutrition Academy here, and listen to all three of them tell their own stories in Episode 261.