Endurance training tips: The benefits of FatMax training and how to do it properly

Endurance sport is exercise – that much is clear. But it involves not only maintaining muscular function, but also, and above all, metabolism. So anyone who improves their physical performance on a bike is, at the same time, constantly working on the way their own body – that is, their cells – generates energy, utilises it and exchanges oxygen and carbon dioxide.

“Understanding metabolism is a crucial aspect of making progress in training,” says our expert, Dr Andrea Jeschke. An important term, particularly relevant for longer-duration endurance exercise, is FatMax. This is short for Maximum Fat Oxidation.

What is FatMax?

FatMax refers to the exercise intensity at which fat oxidation (in g fat/min) – that is, the breakdown of fat to produce energy – is at its highest. It is therefore not the intensity at which your body derives the largest proportion of its energy from fat (which would be the case at rest or at a very slow pace), but rather the intensity at which it burns the most fat per minute in absolute terms.

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Your body constantly draws energy from fat and carbohydrate stores to fuel movement. But the mix shifts depending on the intensity: when we walk very slowly, our overall energy requirement is low – and consequently, the rate of fat burning per minute is also rather low. When we suddenly sprint, the energy comes mainly from carbohydrates (sugar in the blood and glycogen in the muscles). In between, there are training zones where fat burning per minute is particularly high – and that is precisely where FatMax lies. FatMax is therefore not a training zone, but a metabolic state that can usually be achieved at relatively low intensities (such as basic endurance training).

Why is FatMax important for training?

FatMax is so exciting in endurance training because, in practice, it often marks precisely the zone in which you can cycle for long periods in a controlled and repeatable manner – whilst building up your aerobic base particularly reliably: more ‘power’, better efficiency, greater resistance to fatigue. “If we imagine the body as a hybrid engine, it’s relatively easy to understand how this works,” says Andrea Jeschke. A hybrid engine draws on various sources of power. One of the body’s fuels is stored fat. However, when this is used, maximum power cannot be achieved. “If we want to get faster, we need additional sources of energy,” explains Jeschke. FatMax training is, in a sense, about expanding the training zone in which we can rely on our very abundant fat reserves – which even slim people have.

The intensity is at a basic level. The advantage is that FatMax helps you to keep your easy sessions genuinely easy. Because when you train at this intensity, you’re protecting yourself from going too fast. This also means you’ll rack up fewer of those infamous ‘junk miles’: kilometres that feel like a workout but are neither easy enough to allow you to recover properly, nor hard enough to provide a clear performance stimulus. After all, you do FatMax as part of your base endurance training.

And yes: at these moderate intensities, the body builds up precisely the infrastructure that enables endurance performance. Mitochondria (the cells’ ‘powerhouses’) become more numerous and more efficient, whilst the muscles develop a better capillary network – meaning they are supplied with blood and oxygen more effectively. This isn’t spectacular, but it is the foundation on which speed is later built.

What changes will FatMax bring?

In short: your body becomes more efficient. If you train regularly at this intensity, your ability to generate energy aerobically – that is, with comparatively little strain on your cardiovascular system and metabolism – will improve. Aerobic and anaerobic describe whether or not the body can use oxygen to produce energy: there are measurable thresholds for this (if you undergo a fitness assessment, you’ll find out exactly what they are). At a certain point, the body switches to anaerobic energy production – because aerobic capacity alone is no longer sufficient. In the aerobic zone, you can maintain a given pace for longer without it feeling ‘strenuous’.

What’s more, FatMax training can also influence other important markers, which I will explain time and again in these newsletter articles. For example, the aerobic threshold – the point at which the body begins to draw increasingly on carbohydrates, as well as fat, to provide energy. And the anaerobic threshold – the range from which the workload is so high that the breakdown of carbohydrates produces more metabolic by-products than the body can process over the long term: the intensity can then only be maintained for a limited time.

How can you train with FatMax?

The best way to train with FatMax is to cycle at a steady, consistent pace within the appropriate training zone. In practical terms, this means cycling at a pace where you could still sing loudly and continuously (if you dare), your breathing remains controlled, and you can maintain the pace for a long time – ideally 60 to 120 minutes at a stretch, or even longer for advanced cyclists. If you have a wattage or measured value from a sports performance assessment for FatMax, use that as a guide (plus or minus a small margin); otherwise, rely on your well-trained – though sometimes deceptive – body awareness, or, to a limited extent, monitor your heart rate.

Above all, consistency is key: FatMax sessions shouldn’t ‘wear you out’, but should be structured in such a way that you can do them several times a week – this is precisely how you build up your aerobic base and become more efficient over time.

Can I lose weight with FatMax training too?

Weight loss through FatMax training is possible, but it is not the main objective. One should not equate the metabolic effect of the training with the effect of a diet; it works more indirectly and in the long term as a ‘fat-burning trick’. In the zone where you oxidise a particularly high amount of fat per minute, you can usually train for long periods, in a controlled manner and frequently, without completely exhausting yourself each time. It is precisely this that increases your weekly activity levels, improves your aerobic fitness and makes it easier to maintain a moderate calorie deficit over several weeks.

However, the key point remains: whether you actually lose body fat does not depend on whether you burn as much fat as possible during a single session, but on your energy balance over the course of the day and the week. It is therefore important not to confuse FatMax with ‘eating as little as possible’: if you restrict your food intake too much around your training sessions, the quality of your training suffers, hunger often strikes back later – and, in the worst-case scenario, you slip into a chronic energy deficit.

FatMax is therefore a useful tool for sustainable weight management – not a shortcut to rapid weight loss. “Intense workouts are much better for losing weight, as you burn significantly more calories per unit of time,” advises our expert Dr Daniel A. Bizjak from Ulm University Hospital. As always, “it’s all about the mix.”