When Is the Best Time to Workout for Weight Loss?

When Is the Best Time to Workout for Weight Loss?

If you’re wanting to lose weight, lean out or build a more athletic body and you’re not sure if there’s a best time to exercise, this article is for you.

We all know that regular exercise is important for your health, well-being and longevity.

Getting in shape, ramping up fitness and making positive changes to your lifestyle is all about using your time efficiently.

For many people this means trying to squeeze a gym workout in first thing in the morning. For others it means a home-based circuit once the kids are in bed.

But is there really a ‘best’ time to workout for weight loss?

In this article we take a look.

The Basics of Weight Loss

Whether you gain or lose weight is all down to energy balance.

No matter how hard you exercise, if you take in too many calories you’ll just continue to store more fat.

But achieve a calorie deficit – where you burn off more energy in a day than you put in your body – and you’ll trigger a number of enzymatic and hormonal reactions that ultimately result in you using excess stored fat as fuel.

And of course you’ll lose excess weight.

How do you burn more calories?

Known as ‘total daily energy expenditure’, you can burn energy in 4 ways:

  • Primary functions – known a basal metabolic rate (BMR), this refers to the energy you use each day to keep your heart beating, your brain firing and your muscles in their current shape and size.
  • Non-exercise physical activity – all daily activities use energy, no matter how easy they are. Walking, fidgeting, tapping your foot, gardening all need calories.
  • Exercise – whether it’s hitting the gym or the sports field, exercise uses energy.
  • Digestion of food – when you eat, you use a small amount of energy to digest and then absorb the nutrients you’ve just take on-board

The bottom line is that if you burn more calories from any of these aspects of TDEE you’ll increase your chances of weight loss.

Exercise and daily activity levels are obviously the ones you can modify the most.

Your Body Is Continually Shifting Throughout the Course of a Day

While many people might think that the human body is a static machine with little variation, it does in fact work dynamically.

It is constantly trying to adapt to its environment and uses a number of in-built mechanisms to cope better with its surroundings. Your circadian rhythm is a biological process that controls how your body adapts using an ‘internal clock’ over a 24-hour period.

Examples include:

  • Sleep-wake cycle – you body tells you when its time to wake up and when its time to go to bed.
  • Hormonal secretions – testosterone, growth hormone, cortisol and melatonin for example all have different peaks throughout the day.
  • Body temperature – you’re colder in the morning and warmer in the early evening.

Some research has even shown that your metabolism also shifts across the course of a day too [1].

But does this necessarily mean you burn more fat at different times of the day?

Key Points:

  • In order for you to lose weight, you need to achieve a calorie deficit over a prolonged period of time.
  • Your body has an internal clock that controls how your body reacts to stimuli throughout the day.

So What’s The Best Time to Workout?

Let’s be honest here.

For most busy people, working out for weight loss at any time of day can be a challenge. With some many hours at work, family commitments and day-to-day duties to get through, finding time to hit the gym for a good exercise session can be near impossible.

Some suggest that morning workouts might be better

One proposed mechanism for working out in the morning is that it could help you tap into your fat stores easier.

There’s an absolute minimum amount of evidence to suggest this is true (the one or two studies that have been released were in poor quality journals with questionable data collection).

But those that do advocate morning exercise often suggest that fat burning might be higher because your stored glycogen levels are lower (because you’ve not eaten in the last few hours). And while depleted, your body could turn to fat as a fuel instead.

The problem with this though is that so called fasted training hasn’t been show to be superior for fat loss in clinical trials [2].

Some people struggle to go to sleep when they exercise late at night. Their epinephrine levels are higher and they take longer to relax post-workout. And because sleep is important for weight loss, this might not be a good strategy.

So the only benefit to exercising might be that it doesn’t interfere with sleep patterns.

But evening exercise may influence energy expenditure more effectively

A review published in Obesity [3] suggested that even with exercise, it can be hard for people to lose weight because of compensatory effects with eating habits.

What this means is that when you exercise you use stored energy, and to balance this out, your hunger signals increase, forcing you to eat more food.

Neil King, the lead scientist and author of the review went on to suggest in the review that exercising in an evening might be beneficial for weight loss because it could in theory reduce the compensatory effects of energy balance.

“A person who exercises in the early evening may go to sleep earlier or require more rest in the evening.”

So its not that exercising in the evening directly influences weight loss, rather it helps you reduce your appetite and overall energy intake.

And retiring to bed earlier in the evening could influence the impact the acute energy deficit created by exercise and therefore help you drop body fat and weight. But only if you don’t eat a huge amount of food after your workout as a compensatory reward.

Summary – Does it matter when you work out?

The bottom line is that there’s no wrong time to work out.

The fact that you’re motivated enough to lace up your sneakers, dust off your gym bag and get some exercise done is great.

And although the body moves internally within its own rhythms there’s just not enough evidence that suggests an ‘optimal’ time of day for working out.

We suggest you exercise when it’s best ad most convenient for you.

If you’re a morning person and find that you can perform better earlier, then go with it. And if you’re brighter and more productive late at night then that’s the best time for you to exercise.

It’s all about what works for you as an individual.

  1. Eckel-Mahan, K et al. Metabolism and the Circadian Clock Converge. Physiol Rev. 2013; 93(1): 107-135
  2. Schoenfeld, BJ et al. Body composition changes associated with fasted versus non-fasted aerobic exercise. JISSN. 2014; 11: 54
  3. King, NA et al. Metabolic and Behavioral Compensatory Responses to Exercise Interventions: Barriers to Weight Loss. Obesity. 2007; 15(6): 1373-1383