If you ask google what the best exercise for weight loss is it invariably returns lists of exercises that burn plenty of calories. In this post we’re going to dispense with this rather simplistic view and take a broader approach. We’ll begin with the best ‘exercise’ for weight loss, then working through other priorities.
1) Diet for Weight Loss
The single most efficient way to lose weight is to control what you eat. The reason for this is quite straightforward. It’s considerable easier to reduce energy intake that it is to increase energy expenditure.
Let’s take the simple example of creating a 3,500 calorie deficit (roughly the available energy in a pound of body fat). Cutting 500 calories a day from what you eat can be achieved in many ways by control what you eat. In contrast adding 3,500 calories of extra energy expenditure a week will require in excess of 5 hours of strenuous exercise. And even then the accompanying increase in hunger will often wipe out much of the deficit created.
So before you even start to consider which exercise you’ll use during a fat loss phase, you need to have a plan to control what you eat in order to maintain your deficit. For a quick reminder of what the deficit is check out this chart:
The state of energy balance we want for fat loss is the ‘caloric deficit’ on the right. When we are in a deficit we create a calorie shortfall that must be met by stored energy in the body (body fat, muscle protein or glycogen).
Whether or not you are in a deficit is determined by one thing, how many calories you put in your mouth. So technically you could gain weight riding the Tour de France (if you ate enough) and lose weight while stuck in a hospital bed (if you ate very little).
Once people understand this it’s easy to make the jump to thinking exercise is redundant, that you can simply diet your way into shape. This is a mistake. Exercise can help protect your metabolism, ensure you lose fat rather than muscle, improve how your body functions, enhance how it looks and benefit your health. You should always exercise while losing weight, it just needs to be a secondary priority to diet.
For a good overview on why you should prioritise diet first check out VOX’s epic explainer.
2) Strength for Weight Loss
If your goal is to lose weight quickly, then after diet it makes sense to consider cardio. However if your goal is to lose fat, and keep it off in the long run, you’d do well to consider strength training.
The process of losing weight requires you to spend more time in a caloric deficit than in a surplus. As a result your body starts breaking down tissue to use as fuel. The best way to ensure your body uses mostly fat (rather than muscle) is to combine strength training with sufficient protein intake while remaining in a deficit. This process has a second important effect, it helps to protect your metabolism from the ravages of dieting.
Let me give you a concrete example. The graph below is from a study where each group lost about 12 kg (26 lbs) in 21 weeks with a brutal 800kcal diet.
When looked at purely through weight loss the approaches had similar results. But if you look at the lean body mass figures you can see that the resistance training women managed to gain a small amount of muscle while the aerobic and non training groups lost some. They actually gained muscle on 800 calories a day!! If you look at the resistance energy expenditure you can see that strength group also had the small drop in resting metabolic rate (roughly equal to what you would expect from the weight loss alone).
It often comes as a shock to people cardio isn’t actually essential for most people to get lean. If you find this hard to believe have a look at this piece over at Ripped Body. Of course just because cardio isn’t essential doesn’t mean you shouldn’t do it.
For a much more detailed look at strength read our primer on strength training for fat loss.
3) Intervals for Weight Loss
Before we talk about stead state cardio (think jogging, cycling, swimming), let’s talk about interval training. If you are fit enough, and can recover for other workouts, high intensity intervals (HIIT) are worth considering for fat loss.
Numerous studies in recent years have shown intervals outperform steady state in terms body composition. The graph below from a meta study on training interference found that the biggest reductions in body fat from cardio are produced at the highest heart rates.
This supports the idea that cardio seems to become much more effective for fat loss when we cross 90% of our maximum heart rate. At this point the effort is so intense that you are forced to work anaerobically. Although the mechanisms aren’t completely clear it seems that normal aerobic training mostly improves your ability to pump oxygen around your system, whereas more intense intervals create adaptions in the muscle themselves which can improve fat and carbohydrate oxidation capacity. So in many way intervals are working more like strength training than traditional cardio.
Although I think there is a strong evidence base to suggest high intensity cardio is the most efficient cardio for fat loss, that doesn’t mean its always the best tool for the job. If you are heavily overweight, or just starting back in to exercise, low intensity is a much better bet. This can help you build basic fitness while avoiding much of the impact and physical strain associated with higher intensity work. Low intensity work is also ideal for strength focused individuals who need to save their legs for lifting.
If you do decide to try some interval training, make sure you work up to it slowly. Jumping into high intensity intervals after long periods of not training is stupid and dangerous!!
4) Cardio for Weight Loss
Cardio can be a useful tool for fat loss, but there’s a solid argument for considering after diet and strength training. It can also waste a great deal of time and effort if not used intelligently.
The mistake lots of people make with cardio is to assume that if they put in the time on the treadmill the rest will just take care of itself. This approach may work for health, but not for weight loss. In lots of cardio interventions the fat loss results are bordering on non-existent, as people either eat back the extra energy they expend or compensate by expending less energy in other parts of the day.
Personally I feel the whole debate around cardio for fat loss a little misplaced. For me cardio really isn’t a weight loss tool at all, it’s a health tool. Here’s the graph that cemented this long held view in my mind.
This chart resulted from a study using data from 38,000 patients where they looked for evidence of an upper threshold for mortality benefit to cardiovascular fitness. They didn’t find one. The fitter people are the less and less likely they are to die soon.
You can of course make the argument that this isn’t necessarily a causal relationship. There might be omitted health variables, reverse causality from genetics or other things driving the correlation. But its hard to make that argument continuously for the mountain of evidence showing the benefits of cardiovascular exercise.
Cardiovascular fitness can help you live a longer and better life. It’s not a fat loss tool. It’s THE health tool.
Read more about cardio in our cardio for weight loss primer.
5) Walking for Weight Loss
To my mind walking is the single most underrated fat loss exercise on the planet.
Sure it doesn’t burn that many calories, or make your muscles burn, or get you sweating. What it does have is the lowest bar to entry by a country mile.
At any given moment in my life I am seconds from walking. I can add 10 minutes of walking to my day without special clothes or the need for a shower afterwards. I can do it with friends, as a means of transport and I can carry a conversation during it.
If you need a little more convincing look at the next chart.
Among members of the National Weight Control Registry (NWCR), a project that tracks people maintaining a weight loss of at least 13.6 kg (30 lb) for a minimum of a year, walking is the most popular form of exercise. As well as the biggest calorie burner!!
These figures, from one of the first papers the NWCR did, show that people who lose significant weight and keep it off tend to be very active. And the biggest source of that activity is walking (around 1,000 calories a week). The people that participated in ‘medium’ or ‘heavy’ activity were doing mostly cycling, lifting weights, aerobics and running.
Just let me hammer home this point for a moment.
The people in this study had lost an average of 30kg (66lbs) and kept it off for 5.5 years at the time the data was collected. If you know anything about the phenomenon of weight regain, that generally starts around 6-8 months, you’d realise these people are all exceptional!!
And among these exceptional weight loss maintainers the leading exercise isn’t high intensity intervals or heavy lifting, it’s putting one foot in front of the other.
This simplicity of walking is not something to be dismissed. Walking can be integrated into the life of people of almost any fitness level and can be a hugely useful tool for helping to maintain long term weight loss.
What’s the Best Exercise for Weight Loss
What’s the best exercise for weight loss then? Let me try to sum this up with a recommendation I often use with clients who are trying to lose weight:
- Use diet as your primary tool for weight loss
- Try to lift twice a week (2×30 minutes full body)
- Add an hour per week of cardio if possible for health
- Wherever possible add walking or activity to your life
That’s two hours of exercise per week, where strength training takes priority if your busy. It won’t turn you into Mr Olympia but for busy people with families, friends and jobs, the difference between two hours and nothing can be remarkable.