Fat-burning training program: morning cardio

Translated by Janar Rückenberg

A morning fat-burning training program is an old favorite among Estonian bodybuilders — get up, drink a glass of water, put your shoes on and go for a walk or hop on a stationary bike, still without eating. It sounds harsh, but in the pre-contest period many top competitors do it without fail. Does the science back it up? The answer is more nuanced than the forums make it sound.

In this article we look at what actually happens in the body after a 12-hour overnight fast, how the 67% versus 50% figure in the Kansas State University study comes about, why Greg Landry and Lyle McDonald aren’t entirely convinced, and how Chris Aceto sets it all up in practice. Finally, we’ll talk about how to keep your muscle mass.

Why a morning fat-burning training program works

The arguments in favor of morning cardio come down to five physiological facts.

1. Low glycogen stores. After a 12-hour fast, the liver and muscles have given up their fuel — the body turns to its fat stores more quickly, because they’re easier to draw energy from.

2. Low insulin. Eating triggers the release of insulin, and insulin hinders the mobilization of fat from adipose tissue. In the morning its level is at rock bottom, so fat burning is more efficient.

3. Low blood glucose. After an overnight fast there are also fewer carbohydrates in the bloodstream — the body can’t get its hands on easy glucose.

4. No energy eaten. If you eat before training, that energy gets used up first. Starting without food, the body goes straight after the fat stores.

5. A faster metabolism for the whole day. A morning session “kick-starts” your daily metabolism — with an evening workout this effect largely disappears, because the body is already getting ready for sleep.

Research on the fuel mix

Concrete support comes from Kansas State University. Researchers measured gas exchange, calorie expenditure, and carbohydrate and fat metabolism in the participants. When the aerobic session was done in the morning, after a 12-hour overnight fast, 67% of total calorie expenditure came from fat. When the same session was done in the middle of the day or after a meal, fat’s share was only 50%.

A similar study in the journal Applied Physiology examined fat metabolism in fed and fasted states. The conclusion was the same: 12 hours without food significantly boosted the effect of aerobic training on fat oxidation.

The number is clear. The dispute is over whether it also means more fat lost in the longer term.

Counterarguments: Landry and McDonald

Exercise physiologist Greg Landry agrees that fat makes up a larger share of the fuel mix in a fasted session, but doubts whether that decides the whole picture. According to Landry’s theory, all the calories stored in the body sit in one big pool, as it were — if more fat is used in the morning, correspondingly more carbohydrate is used later in the day, and vice versa.

Bodybuilding and nutrition specialist Lyle McDonald takes the same line. According to McDonald, what matters more is the 24-hour calorie turnover: if you burn more fat in the morning and your total daily calorie intake stays below what’s needed to maintain body weight, the body uses more glucose over the rest of the day. If more carbohydrate is used during the workout, fat gets burned later. In McDonald’s view, the result is the same.

McDonald points to sprinters as an example: they don’t do fat-burning workouts and train mostly on carbohydrates, yet they still have an extremely low body fat percentage. Energy balance comes from the whole day, not from a single session. According to McDonald, the main benefit of morning cardio is rather a psychological one.

Aceto’s practical fat-burning training program

When it comes to practice, Chris Aceto is a different story. Aceto is both a bodybuilder and a nutrition specialist, has taken several bodybuilders to the top, and is a firm believer in morning cardio. According to Aceto, a fasted morning session is the quickest and most effective way to get rid of unwanted body fat.

Aceto thinks that reducing all fat loss to calories in versus calories out is shortsighted. The classic argument: are all calories equal? They are not.

One example. Say my body weight holds steady on 2500 kcal a day. If the energy balance theory were the whole story, I should be able to eat nothing but chocolate cupcakes and drink Coca-Cola worth 2400 kcal, stay 100 kcal below maintenance, and the fat would melt away. In real life it doesn’t work that way. Food quantities, nutrient ratios, meal frequency, glycemic index — all of these affect the end result. When dieting, Aceto recommends 5–6 meals a day instead of the traditional three, so that muscle mass suffers less.

Aceto’s practical fat-burning training program is simple: at least one aerobic session in the morning, fasted, lasting up to 30 minutes. We’ll come back to this in the section on muscle mass.

Other benefits of a morning fat-burning training program

Even Landry, who questions the fuel-mix argument, would put one cardio session in the morning. There are several reasons besides fat burning:

1. It releases endorphins — your mood and spirits lift for the whole day.
2. It “kick-starts” you — the physical wake-up is usually stronger than coffee.
3. It helps regulate your appetite throughout the day.
4. In the longer term your biological rhythm adapts — getting up in the morning becomes easier.
5. It’s a sure bet: in the morning your body is rested and nothing else in your day gets in the way.
6. There’s always time if you set your alarm earlier.
7. It speeds up your metabolism for several hours after the session.

The last point — the post-session metabolic boost — deserves a section of its own.

EPOC, or the afterburn

The increased oxygen consumption after training is called excess post-exercise oxygen consumption, or EPOC. In older literature you’ll find it under the name “oxygen debt”. The idea: after a session your body keeps burning calories because it has to recover.

It sounds impressive — you’re already sitting at your office desk and still burning calories. The bad news: the effect isn’t as big as some articles promise. The myth that your metabolism stays elevated for 24 hours after moderate-intensity cardio only holds for very long, intense training loads (a marathon, for example).

An ordinary easy, low-intensity walk gives you practically nothing in terms of EPOC. A cardio session at 60–65% of maximum heart rate adds only 10–30 kilocalories.

Things change as intensity rises. According to a study by Wilmore and Costill, after a session at 75–80% intensity you get an extra 0.25 kcal per minute, or 15 kcal per hour. Translator’s note: unfortunately the source doesn’t say how long an afterburn at this rate lasts, but judging from the calculations that follow, I conclude it is five hours.

15 kcal per hour over five hours adds up to 75 extra kilocalories. Trivial at first glance. But if you train like this every day for a year, that comes to 75 × 365 = 27,375 kcal. Divided by 9 kcal per gram, that gives 3000 g, or 3 kg of fat, burned purely thanks to the afterburn.

HIIT can boost the results of a fat-burning training program

One way to strengthen EPOC is the interval method, or HIIT (high intensity interval training). The base level stays at, say, 65–70% of maximum heart rate, but every 4–5 minutes the intensity is raised to 85–100% for 2–3 minutes. On an exercise bike this can mean pedaling faster or increasing the resistance.

Translator’s note: when I was preparing for the spring Cup competitions in 2005, I used this method for my own cardio work as well, and it was very effective.

Researchers at the University of Alabama compared two groups. The first rode an exercise bike for 60 minutes at moderate intensity. The second used the HIIT method, alternating 2 minutes at moderate and 2 minutes at high intensity. Over 24 hours, the HIIT group burned 160 kcal more.

Do the math: 5 days a week all year gives 260 workouts. 260 × 160 kcal = 41,600 kcal a year. Divided by 9 kcal = 4622 g, or 4.6 kg of fat purely from the afterburn. The calories burned during the ride itself aren’t even counted in yet.

Strength training as part of a fat-burning training program

One unexpected fact: strength training has an even bigger afterburn effect than cardio. Studies show a 4–7% increase in metabolism over the following 24 hours.

In practice: a man who consumes 2500 kcal a day gets 100–175 extra kilocalories from the afterburn of a strength session. Bodybuilding training therefore burns fat even without separate cardio — through indirect mechanisms. If you want to reduce body fat, you can bet on weights first and add cardio only when that isn’t enough.

How to avoid muscle loss

The most common concern with fasted cardio is losing muscle mass. After sleep, glycogen and insulin are low and cortisol is high. Cortisol pries amino acids loose, and the body uses them for energy. In that sense, a morning session is a double-edged sword.

Muscle loss can be avoided. A few rules keep the balance on the anabolic side.

Limit the length of your session. Aceto recommends keeping fasted cardio to a maximum of 30 minutes. Beyond that, the catabolic side starts to win.

Coffee before training. A cup of strong coffee before cardio prevents glycogen from being used as an energy source. If the body spares carbohydrates, it also spares protein — it doesn’t have to pull amino acids out of your muscles.

Eat properly for the rest of the day. Muscle loss on a diet is usually caused by inadequate nutrition, not by too much cardio. When your meals are in place, your macro split is sorted and your total calories are reasonable, the loss stays minimal.

Keep training with heavy weights. In the fat-burning phase, you shouldn’t back off from heavy weights. First, it helps you hold on to muscle. Second, it’s muscles that burn fat for energy. Less mass, less fat-burning capacity.

Protein before the session. Another common strategy: 30–60 minutes before morning cardio, you have a small protein meal, protein only, with no carbohydrates. Insulin doesn’t rise from it and fat mobilization isn’t disrupted, yet amino acids are present in the bloodstream to prevent muscle “breakdown”.

FAQ

Is a morning fat-burning training program suitable for beginners too?

Yes, if you’ve already been training for a while and your nutrition is in order. For a beginner who isn’t yet doing strength training and whose diet isn’t structured, it’s more important to lay the foundation first: meals and three to four strength workouts a week. Morning cardio can be added once your body fat percentage simply stops dropping.

How long should a morning session last?

Up to 30 minutes if you train fasted. A longer fasted session starts to eat into muscle mass. If you want to do longer cardio (45–60 minutes), eat a small protein-based meal beforehand or split the session into two parts.

HIIT or regular cardio?

Both have their place. HIIT produces a stronger EPOC and fits into a shorter time slot: according to a University of Alabama calculation, 160 kcal more over 24 hours. Regular steady-pace cardio is a more moderate training load on the nervous system and fits into a busier week. One HIIT session and a couple of easy walks a week is usually a good combination.

Finally: the heated debate on this topic continues, and a definitive answer will need further research. Logic, practical experience and the available studies give me reason to believe that the timing of aerobic training matters. Focusing solely on energy balance seems too narrow. When you’re dieting in a competition period, the key factors are the glycemic index of foods, dietary fiber content, total calories, macro split and the nature of your carbohydrates (simple or complex), along with the ability to time your nutrition across the day. A morning session is a worthwhile part of that picture, not a silver bullet.

Author: Janar Rückenberg

Source: WHO – physical activity.

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