Exercising to Burn Body Fat: HIIT vs Strength vs Cardio

Estimated reading time: 6 minutes

When it comes to learning how to lose body fat through exercise and diet, there’s conflicting information everywhere. One friend will tell you to cut all carbs and drink protein powders, another will say you need to do seven hours of cardio a day, and one person will gleefully tell you that they eat whatever they want without ever gaining weight.  

Your body composition (body fat vs skeletal mass vs muscle mass) is influenced by lots of factors. Some of these are outside of your control, like genetics. However, there are two things you can change to improve body composition: nutrition and exercise. Here we’ll focus on exercise.

Though the saying ‘you can’t outrun a bad diet’ is true, exercise is an important part of a healthier lifestyle overall. Plus, exercise helps you to create a calorie deficit so you can lose weight and increase your lean muscle to body fat ratio, improving your overall body composition.  

What is a healthy body fat percentage?

You might think it’s a case of ‘the lower the better’ when it comes to body fat, but that’s not true. Having too little body fat can cause problems like:

  • nervous system damage
  • low blood pressure 
  • hair loss
  • frequent illness 
  • vitamin deficiencies
  • heart disease
  • fertility issues
  • fatigue

For women, a healthy body fat percentage is around 21-35% and for men, 8-24%. Rightly so, there’s quite a bit of variation in those figures. There are plenty of different healthy body types and body fat will depend to some degree upon your genetics, lifestyle, and goals. 

What exercise is best to improve body composition and reduce fat?

Broadly, exercise falls into three main categories: HIIT, cardiovascular, and strength. Which is best to help you burn fat and meet your body composition goals?

High intensity interval training (HIIT)

Man exercising outdoors with battle ropes for cardio and strength workout

HIIT workouts typically combine short bursts of intense exercise with periods of recovery or lower-intensity exercise. During the work periods, you’ll be training at almost your maximum capacity. Alternating sprinting, walking, and sprinting again. 

Some research has shown that HIIT burns up to 30% more calories than other forms of exercise, and HIIT may be the most powerful exercise type for reducing fat, especially visceral fat. Because it can be modified to suit any workout, you can also train a variety of muscle groups. 

Strength training 

Women in gym lifting large weights

The term ‘strength training’ may conjure up images of bodybuilding competitions. ut rest assured that you don’t have to lift huge weights to reap the benefits. Strength or resistance training is anything which requires you to contract your muscles against a force or support your body weight. This includes weightlifting, workouts with resistance bands, bodyweight exercises (e.g. pushups and squats) and even yoga. 

Research shows that weight training promotes muscle growth, which helps you burn more calories at rest. The increase in metabolic rate can be as much as 7-12%.

Cardio: low or high intensity to burn fat and improve body composition?

Two women running outside on concrete. Running is good cardio and can help you lose weight but should be combined with strength workouts
If you do 30 minutes of exercise, you’ll burn more overall calories (and fat) doing a higher intensity workout

If you want to improve your body composition and burn fat, creating a calorie deficit through cardio (also sometimes called endurance or aerobic activities) can help. So are you better off doing a fast run for 20 minutes or a jog for two hours? 

It’s true that exercising at a lower intensity burns a higher percentage of fat than carbohydrates. Read more about that process in detail if you want to understand the effects of oxygen, breathing, heart rate, and more. 

However, the main thing to remember is that fat contains more calories per gram than carbohydrate so your returns are better. If it sounds too good to be true, that’s because it is. 

The trade off? You have to exercise for longer. If you do 30 minutes of exercise, you’ll burn more overall calories (and fat) doing a higher intensity workout. The same 30 minutes at low intensity would give you a better ratio of fat to carbohydrate burned, but you’d still burn less fat and calories overall. If you do only twenty minutes of running but will jog or walk at a lower intensity for 60-90 minutes, however, then you might see better benefits from lower intensity workouts. Some good examples of cardio include running, swimming, cycling, and sports like kickboxing or soccer.

Woman punching bag with gloves on for cardio exercise

Other things to consider when exercising for fat loss

So what should you do? The best approach is one where you exercise 3-5 times a week with a mixture of strength and cardio to reap their different benefits. 

Keep in mind that HIIT training can be modified to include strength training quite easily so you get the best of both worlds. You have two main options. The first? Taking your regular strength workout and making it into a HIIT workout.

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The second? Taking a HIIT workout and adding resistance or weights. You can do this by:

  • Shortening the rest periods on your usual strength workout
  • Going for less reps of heavier weights at an ‘all out’ effort between rest periods 
  • Adding weights, resistance bands, or bodyweight exercises between cardio (e.g. alternating weighted squats with sprints, cycling, or jumping jacks)
  • Using plyometric movements like box jumps and jumping lunges (with or without weights)

If lifting weights in a gym is your worst nightmare, find something else – maybe you’d prefer an outdoor bootcamp or a rebounding session instead. 

People kayaking on a river which is a good outdoor cardio exercise and has an element of strength due to the water resistance too
If lifting weights in a gym is your worst nightmare, find something else – maybe you’d prefer an outdoor bootcamp or a rebounding session instead

Finally, remember that it’s difficult to burn calories and gain muscle just from one workout a day. That doesn’t mean you should skip working out entirely. 

What it does mean is that you can make a huge difference in the other 23 hours of the day too, just by making a conscious effort to be more active.

You know the tricks: take the stairs, park further away from the shop entrance, walk to the furthest water cooler, and take phone calls while pacing. 

After all, reducing body fat percentage and improving your overall body composition is a lifestyle change – not simply an eating plan or exercise regime.