A Complete Guide To Fasted Training

19 min read

This Article Will Address

  1. There’s much more to this activity than burning belly-fat
  2. The many metabolic benefits of training fasted
  3. How to get the best out of these workouts
  4. The ultimate fasted training protocol

Why Train Fasted?

Why would you want to work out on an empty tank? What’s a muscle without fuel?

Putting the body in a state of scarcity actually triggers a whole bunch of metabolic machinery that can ultimately get you building more muscle and burning more fat. Through the fire, you become stronger.

Don’t let the fear of collapsing in a limp heap put you off. Training fasted is a potent tool that’s far from an extreme sport. The body has huge reservoirs of energy waiting to be used, many times whatever you could throw in the breakfast bowl. What you’re doing is forcing the body to use its own fuel, which can be a game-changer.

Skipping breakfast could mean a few extra minutes in bed. Perhaps you could go for a morning stroll and catch some early sun instead. Or meditation may finally get its own slot.

But fasted training has more going for it than convenience alone. It’s a metabolic upgrade. And while it doesn’t have to be your default option, you should absolutely consider throwing it into the mix on a frequent basis. There’s just too much opportunity to turn down.

Through this guide, you won’t just learn about the merits of fasted training, you’ll be getting the best possible protocol for making use of those workouts. I’ll be drawing on all the years I’ve already spent training on an ‘empty tank’, and a metric ton of research to back that up. Which means one or two case studies.

The Benefits Of Fasted Training

  • Time saver
  • One less meal to worry about
  • A potential fat burner
  • One of the few ways of losing stubborn fat
  • Metabolic flexibility
  • AMPK booster
  • Adrenaline kick
  • Resilience builder

My case for fasted training is this: it works regardless of whether you’re looking to gain muscle, or burn fat. It’s a way of adapting the body through stress, building a system that can thrive under pressure. That’s why I include fasted training in the apex lifestyle package.

See My Article – Can You Fast And Build Muscle?

The Metabolic Upgrade

Fasted workouts often get framed as a tool for targeting belly fat. Something you’d throw in near the end of the diet, just to hurry things along. And while that much is true, there’s much more going on under the hood.

So a typical fasted training session will see you skip the midnight snacks, turn down breakfast, then rock into the gym for a workout. At this point, insulin will have disappeared from the bloodstream, hence the term ‘fasted’.

This can initially be a grueling ordeal. When you’re so reliant on carbs for energy, that you can’t train without a bowl of oats sitting in your stomach, or a bottle of lucozade wedged in your free hand, then there’s clearly an issue. 

There’s an ocean of energy nestled around your midriff, waiting to be tapped into. And as long as you insist on topping up on carbs every few hours, that’s not happening. 

Eating a meal that includes carbs will typically spike insulin for 3-4 hours afterward. Insulin, which is inherently anabolic, keeps the fat-burning switch turned off. For more insulin resistant individuals this can put the brakes on fat loss altogether. Even if you’re in a relatively healthy frame, progress just won’t be at its optimal.

This is where we get the whole tradition of 6 am fasted cardio for burning the stubborn holdouts of the spare tire. 

Don’t get the wrong picture here. Training after eating a meal is also fine, you’ll still have plenty of time outside the session for the body to switch to fat-burning mode. But that window gets uncomfortably tight if you’re constantly hopping from meal to snack, then back to the next meal. This is how insulin resistance develops.

That’s not the end of it for fasted training’s effects over metabolism. Go for any decent intensity on an empty stomach, and the body is put under an extreme state of stress. The positive, resilience-building kind. 

Much of that stress can be linked to the activation of the AMPK pathway, or as I’ve labelled it, the famine to all that feasting you’re doing. AMPK is triggered by both fasting and training, and combining the two makes for powerful adaptations to the mitochondria. The powerhouses of the cell experience biogenesis (hypertrophy for cardio), and an uptick in activity. 

This AMPK activation also signals the transition from glycogen utilisation, over to triglycerides and ketones. So fasted training enables you to better utilise fat cells. That’s not to say you burn more fat. The body simply becomes better at using fat for energy. This effectively gives you stable energy levels and prevents the sort of crash you’d expect after a brutal session. Because, whenever necessary, the body can switch from glucose to fat while maintaining stable blood sugar. 

So the stakes are much more than potentially losing an extra pound every month. Side-stepping the energy crash lets you push your workout towards greater and greater intensities. Rest intervals are shorter, and the overall volume gets driven up. This metabolic upgrade ends with you netting more strength and muscle.

The Metabolic Effects Of Fasted Training

Raised Insulin Sensitivity
More Mitochondria
More Fat Burnt
Better Fat Burning
Better Ketone Utilisation
Higher Ketones

If you’d like to delve more into fasting as a diet upgrade, I’ve written out a free 87-page guide for just that.

The Fast Way To Fat Loss

Won’t Fasted Training Make You Weaker?

Since going for a trundle on the treadmill shouldn’t use much glycogen, you might as well stick to doing it fasted whenever opportune. You burn some calories, while gaining metabolic upgrades, with no downsides. But wielding heavy dumbbells makes for a different matter. There will be some glycogen cost, and training fasted naturally puts you at lowered levels. So you’d expect a performance decrease.

For this reason, you don’t have to stick to fasted training. The optimal strategy would be to cycle between fasted and non-fasted workouts. That’s the whole ‘train high, train low’ paradigm. Training low (glycogen), would be great for stamina and fat utilisation, while training high can be used for power.

But there is something to be said for a consistent training environment. Each time you wake up an hour early for some lifting, the body gets a little bit more adapted and attuned. It becomes more alert, stronger. The same thing happens with fasting past a meal. Repetition is rewarding. The brain likes to short-circuit repetitive actions in order to save energy. This is how new habits are formed.

Moving past the merits of a routine, there’s no excuse for slugging through a fasted workout. At least there won’t be, once you learn the strategies that can prime the body to perform and thrive in this state. Here’s where the ropes of fasted training can become more intricate than ‘sleep, skip breakfast, train’.

It wouldn’t be much of a takeaway for an article of this size.

The following tips will work, whether or not you choose to cycle between fasted and non-fasted workouts, or keep it as your default blueprint. Maybe once in a while you treat yourself to an early breakfast, but on most days you put the work in before relaxing.

Make Use Of Adrenaline – When To Train

In order to lift heavy, or intensely, you’ll need plenty of fuel. That might be lacking if you’re not particularly fat adapted, or there’s not much fat to use. As luck would have it, there’s a replacement that can more than make up for the drawbacks.

Stress is an entirely negative thing for many in the modern population. There is no longer a risk of being chased down by a lion, but the ancient reflex remains wedged in the brain. Unfortunately, with the wrong mindset, you can interpret anything as a threat to your survival. Whether that would be stopping you from rising to the top of the tribe of chimps, or snuffing the chance to procreate and stay in the gene pool. 

So the stress switch is constantly turned on. Adrenaline and cortisol are constantly leaked into the bloodstream, and chronic levels lead to all kinds of suppression and inflammation. 

What’s the fix? Some choose to try and avoid the triggers of stress altogether. That’s a terrible idea. That makes for a submissive chimp, weighed down at the bottom rung of the tribe. Stress is a tool. You confront it, the body gets better at dealing with it. 

This leads to the whole notion of building resilience, the path of the apex mindset. Mastering the mind has to involve a decent degree of discomfort. It’s reps for the brain.

The secretion of adrenaline and cortisol is a pivotal performance enhancer. It’s the fight reflex. The heart rate goes up, fat burning gets enhanced, and the muscles become more explosive. That’s the perfect setup to power the body through a workout.

As things happen, we have two of these good-stress triggers. Fasting, and training. As we’ve covered earlier, they’re both part of the AMPK (stress) pathway. So what does this mean? 

There’s now a chance to kill two birds with one stone. Use raised levels of adrenaline and cortisol to hit peak power, and upgrade the body’s stress tolerance.

We happen to have a study that perfectly illustrates that point. When comparing athletes training fasted and non-fasted, the bloodwork was telling. In the fasted group, adrenaline was higher before the session. That’s expected. But four hours after the workout, they had lower levels than the breakfast faction. 

That’s the formula that should be followed for any fasted exercise. Time it alongside peak adrenaline output. Afterward, I’d highly recommend eating something within a few hours in order to blunt cortisol levels and get back to a low-stress state.

Cortisol itself will also improve energy during the workout itself, hence why it’s best to have the fasted workout in the morning, coinciding with the apex of the cortisol curve.

Fasting-induced adrenaline tends to peak around 16-18 hours, at which point another player can come to the energy party. Ketones, broken down from fat cells. These wonderful molecules are extremely efficient sources of fuel that can bypass the blood brain barrier. This essentially means the brain gets a steady drip, and you don’t bonk midway through the workout when glucose runs out.

The level of ketones is going to hinge on the diet. If you’ve been on keto for at least a few weeks, then there’s going to be a lot of them swimming around. Ketones are enhanced by fat adaptation caused in a low carb diet.

If you’re on the standard package of carbs and protein, then it would be worth lowering those carbs to around 100-200 grams. Otherwise you’ll be extremely saturated with glycogen, meaning glucose, and ketones won’t have an effect until its been cleared. Which takes more than 16-18 hours.

For The Keto Folk – There’s an extra incentive here for keto dieters. The issue with low carbs and ketones, is that it can have a sedative effect. Great for dealing with anxiety, not so ideal when you have to get angry before a heavy set of squats. Ketones in particular lower glutamate (the gas pedal) and raise gaba (the brake). 

Drawing on the morning fasted adrenaline surge would be a very effective way of sidestepping this issue. It’s a whole lot of gas pedal that overrides the inclination to sit down and start meditating.

Takeaway – Train between 6-10AM to get the most out of cortisol’s energy boost. In order to ensure that this matches up with fasting’s effect on adrenaline output, have your last meal around 4-6PM the previous day. This lets you work out around 16-18 hours into your fast, where both adrenaline and ketones will start to spike. The cumulative effects will easily make up for any performance decreases from an empty stomach.

If you’re new to the realm of ketones, check out my article for a recap on its many benefits.

Ketones Vs The Brain

Does Coffee Break The Fast? – Supplement Guide

Getting up at an unholy hour is hard enough. Starting the day without a warm brew to charge things up, that might be a bridge too far. 

Fortunately, there’s nothing that can frame a cup of black coffee as a fast-breaker. Caffeine acutely improves ketosis, effectively making you better at fat burning. It doesn’t contain sugar in its natural form, so it doesn’t bring insulin into the picture. Even better, coffee triggers AMPK. We’re all on the same side here.

But a black coffee is quite basic, and we’re going to add a few extra layers, just so we can get the ultimate mug of dynamite to gear the body for action.

1 Tablespoon of Butter / Beef Tallow / MCT

Surely now that we’re adding calories, the fast is over? Pure fat has no effect on insulin, and doesn’t stop autophagy or AMPK. Just don’t opt for double cream, that has some sugar in it. 

A little dose of fat will enable you to stay in fat-burning mode, and can quell your appetite for a few extra hours. You don’t really want to be training hungry. As for which of those three options will suit you, that’s going to depend on the diet. 

Non-Keto – MCT is the fast-acting source, and works best for people who aren’t fat adapted. It’s the closest thing you can get to a carb with spiking insulin.

Keto / Dairy Intolerant – Beef Tallow is a long-chain fatty acid, so it will take longer to absorb. But it also has a significant effect on appetite suppression and fat oxidation. Saturated fats are the ideal fat source for the body, and should be a major part of the diet as it is.

Keto / Dairy Friendly – Butter might play funny with some of you, but it’s among the easiest dairy sources to digest. Chances are you’ll get through the workout without breaking out into hives. In terms of fat quality, it’s pretty identical to beef tallow, both being long-chain saturated fats.

½ tsp Electrolytes

A pinch of salt could well be more valuable than dunking a wad of butter in your coffee. The body can become dehydrated during fasting, and the issue isn’t the loss of water. It’s the little electrolytes that get flushed along with it. Running low means you’ll be weaker, and more liable to collapse in a heap after a set of deadlifts. On the other hand, arrive to the session with your electrolyte levels topped up, and chances are the strength and pump will exceed expectations.

Fortunately any drama is made a non-issue if you add a decent mineral salt in the coffee stack. There’s always the option to buy a dedicated electrolyte powder, but Himalayan pink salt will get the job done.

Early Birds And Late Owls – Planning The Perfect Session

The best time for training may not necessarily be the morning, as there’s still the muddle of chronotypes. Basically, depending on your genetics, you could be more suited to morning, afternoon, or evening workouts. This chronotype will effect motivation, and strength levels.

Consistently setting the alarm for a break-of-dawn slugfest should gradually erode those biases. Eventually the differences will be minimal, even if you’ve been predestined to train at sunset. 

Moving past chronotypes, there’s still some evidence with evening workouts showing increased force-output. Morning sessions on the other hand, perform better with technique-based movements. This is due to mental performance decreasing across the day. After that delayed breakfast, everything’s downhill.

However there’s another layer to this, as extended warm-ups have been shown to level the playing field between the AM and PM crew. The decreased power is mostly down to body temperature, hence why performance peaks alongside the temperature curve across the day. Spending a few extra minutes on full-throttle intervals will go a long way towards getting the body in prime condition for training.

Takeaway – Due to the difference in chronotypes, fasted training may not necessarily be for you, but it’s worth pushing through a few weeks to see if it’s just a mental block. 

The session should begin with a warmup of at least 10 minutes, at 7-8 RPE. Ideally you’d be feeling the first few prickles of sweat by the end. Use something relatively safe, like an elliptical.

When possible, use the session for a hypertrophy workout. That means moderate weight, high reps, with extra focus on time-under-tension. For example you could do eccentric reps, taking 3-4 seconds to bring the weight to the bottom of the movement. This will take advantage of the fact that mental prowess peaks in the morning. Supposedly. Maybe with enough coffee.

Everything Still Hinges On Sleep

Let’s say you follow these steps to the letter. You cancel your evening dinner plans, then wake up and dunk the butter in your steaming mug of salted coffee. That should be enough to get you entering prime time as you walk through the gym doors. Except we’re still relying on sleep to come through.

To put it simply, insufficient bedrest impairs every process of your biology. That might seem dramatic, but it’s more of an understatement. Let’s just look at a few of those downgrades, at least the ones that directly impact the session.

The Effects Of A Rough Night On Training

Raised insulin resistance – you’re hungry, and less likely to burn fat.
Increased fatigue – you run out of gas before getting past the warmup
Less explosiveness – heavy suddenly feels a lot heavier

Give proper sleep hygiene the respect it deserves, because it should always be resting at the top of the priority shuffle. And I realise that telling an insomniac to sleep better isn’t too different to telling an alcoholic to stop drinking. The best advice I could give here, is simply to have a consistent evening routine that signals the body to commence the wind-down. Avoid bright lights after sundown, throw in a stretching routine, read a decent book, sit down for some meditation, it’s all to put you in resting mode.

Takeaway – Aim for 7-8 hours of consistent sleep, and avoid blue light and other factors that can raise alertness in the evening.

Giving The Plan Some Wheels

I’d highly recommend including fasted training in your weekly programme, even if it’s just once. The metabolic benefits make it an asset regardless of whether you’re trying to add or cut weight. And if you haven’t got much of a choice in the matter, and you have to get your workout in early, then rest assured that performance doesn’t need to suffer on an empty stomach.

In fact, anyone training in the early hours, might as well train fasted. Whatever you eat for breakfast isn’t going digest in time to offer much of a boost, and it’s more likely to weigh the stomach down and feel sluggish.

The Takeaway

Fasted training is convenient for early birds, and is a potent way of improving stamina, digestion, fat burning, and insulin sensitivity.

In order to ensure you don’t come in demotivated and feeble, time the fast to match up to the morning adrenaline surge.

A bulletproof-style coffee with added electrolytes will be a better energy source than a bowl of cornflakes.

Here’s an example of a routine that puts all these elements to create a prime-time fasted workout.

4 pm – Last Meal – Low Carbs (Beef & Beef Burgers)

8 pm – Dim Lights – Blue Light Glasses

10 pm – Sleep

6 am – Wake Up

7 am – Coffee (Butter, Salt)

7:30 am – 5 Minute Warm Up On Elliptical (30 Seconds Intense, 30 Seconds Steady)

7:35 am – Hypertrophy Workout – (8-12 Reps Per Set)

8:30 am – Wrap Up

11 am – Break Fast

For a similarly extensive guide on fasting, head to this article.

How Long Should You Fast?