How Long Should I Be In A Calorie Deficit?

If you are planning to start a weight loss diet then you will be aware that you need to eat less calories than you take in.

You should have a rough idea of how much food you need to eat every day to lose weight.

How Long Should I Be In A Calorie Deficit?

You may have everything planned out, but that one question still remains unanswered. How long should I be in a calorie deficit?

If you look online you will find many different ideas as to the ‘ideal’ length of time you should remain in a calorie deficit before giving yourself a well deserved break.

There are people who say you should be on a diet for no longer than 12 weeks and then there are those who say you can diet for as long as you choose to.

Finally there’s people who state that you should only remain in a deficit for a few weeks at a time until taking a break from your diet, giving your body a rest and then powering through another streak of dieting.

So how long should you spend in a calorie deficit, it simply boils down to how quickly you can lose weight without losing muscle.

This depends on how much fat you have to lose and how much you want to lose.

Instead of giving you a straight answer like ‘12 weeks’ we are going to break down how long you should be in a calorie deficit and what being in a deficit can do to you.

Only Be In A Calorie Deficit For As Long As Necessary

The easiest answer to the title question is to only remain in a calorie deficit for as long as you need for weight loss, going beyond the time frame can bring about some side effects.

Calculating How Long You Should Remain In A Calorie Deficit

The safe rate for weight loss is between 0.5 and 1kg per week. It’s best to keep these figures in mind as we show an example:

  • Assume your current body weight is: 70kg
  • Your current body fat percentage is: 30%
  • And your body fat percentage goal is: 20%

This would mean that you would need to lose 10% of your body weight in fat mass.

The fastest possible scenario is losing 1kg per week, this would take 21 weeks of eating in a calorie deficit to lose weight.

Using the slowest possible scenario of losing 0.5kg per week would take 42 weeks of eating in a calorie deficit for the desired weight loss.

So this is the general guideline that you should follow to work out how long you should be in a calorie deficit to lose weight.

This approach can be unsustainable and can cause you to fall off of your diet, it can also lead you to be stuck in a calorie deficit for an indefinite period of time due to you not being able to reach the desired weight.

Is Being In A Calorie Deficit Dangerous?

You may be wondering why it could be dangerous as the amount of food you are eating is still a healthy amount.

Well the negative consequences of partaking in a calorie deficit are not as apparent as first thought.

Physical Health

Physical Health

The longer you stay in a calorie deficit the greater your risk of losing muscle mass.

This means that you could be losing weight but the weight you are losing is more muscle than fat leaving you with a ‘skinny fat’ physique.

Even if you are considered in the healthy BMI category, a person with a higher percentage of fat mass relative to muscle mass can still be at a greater risk of suffering from chronic diseases.

These issues highlight the importance of avoiding being in a long term calorie deficit.

Mental Health

Being on a diet can affect your mental health in many ways, constantly being mindful of what you eat, planning your schedule around your calorie budget and even having to refuse food from your loved ones.

There is also the consideration that eating in a calorie deficit can start to affect a person mentally.

There is a real issue that people partaking in a calorie deficit could develop an unhealthy relationship with food or worse their own body image if they feel they are not progressing fast enough in their weight loss journey.

What If It’s Taking Too Long?

If we refer back to our example from earlier, if you lose only 0.5kg per week you would be in a calorie deficit for 42 weeks.

This does not truly put into perspective how long that truly is. 42 weeks is 294 days or 10 months and 2 weeks. That is nearly a year of being in a calorie deficit.

That is an incredibly long period of time and can seem impossible so it can be smarter to opt for a diet break.

A diet break is where you will eat in calorie maintenance for a period of time before jumping back into a calorie deficit for whatever time period you would like.

Being on a diet break will lengthen your overall dieting time, and you will spend more than the proposed 42 weeks losing but a diet break can help circumvent the physical and mental side effects we listed earlier.

So for your own well being it may be more about your own well being instead of the time spent dieting being shorter.

Final Thoughts

Whether you choose to engage in a calorie deficit or not hopefully you are now aware of the benefits and risks attached to being in one.

We have provided you with a formula to work out how long you would be in a calorie deficit for so the choice is yours.

It also best to way up would you prefer to do your diet in one big chunk or break it up with a diet break where you trade a longer time dieting for your sanity.

Jenna Priestly
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