As with most things in the fitness world, when it sounds too good to be true it normally is. But there are always exceptions: science dictates you really can lose weight without exercising. Many people lack time, energy, or are hindered by injuries and can't make it to the gym or out to the fresh air. This article is a weight loss guide for those women and men, seeking to lose belly fat via a weight loss diet plan independent of any exercise.

You've heard it 100 times: "You can't lose weight unless you're in a calorie deficit!"

And it's true.

So, the first step is to know exactly how many calories you burn a day and then set your calorie deficit from there. The amount of calories you burn a day is referred to as your Total Daily Energy Expenditure (TDEE). And you work out your TDEE by following the below steps:

Step 1 = Work out your Basal Metabolic rate (BMR). This is the number of calories your body needs to stay alive for organ functioning. You'll work out your BMR by multiplying your body weight by 20.

For example, Jessica is 75 kg.

75 kg x 20 = BMR of 1500 calories.

Step 2 = Work out the Thermic Effect of Feeding (TEF). This is the number of calories you burn daily from the food you eat, given the energy generated by the body to digest it. So simply multiply your BMR by 0.1 to get the TEF.

Jessica's BMR = 1500 calories.

1500 calories x 0.1 = 150 TEF

1500 BMR + 150 TEF = 1650 calories so far.

Step 3 = Work out the Exercise Energy Expenditure (EEE), which is how many calories you burn during exercise. Now, given you are not doing any exercise at all, we will skip this step entirely. 

Step 4 = Work out your Non-Exercise Activity Thermogenesis (NEAT). This is the number of calories you burn daily away from exercising. It's things like tapping your foot to music, chewing gum, maintaining posture sitting at your desk, and walking to the bathroom.

Desk job employee = 250 calories from NEAT

A parking inspector, delivery driver, building site worker, etc = 500 calories from NEAT

how to lose weight without exercising

Let's say Jessica has a desk job. Our numbers now look like this:

1500 BMR + 150 TEF + 250 NEAT = 1900 calories.

Therefore, Jessica's TDEE is 1900 calories.

Such is powerful information, and now all Jessica must decide is how quickly she wants to lose the weight.

If she has a wedding coming up in a month, she'll want to lose weight faster and thus chose a more aggressive calorie deficit. Here are her options:

Small deficit: 10-15% below daily activity

Moderate deficit: 20-25% below daily activity

Large deficit dieting: 25% below activity or greater (1).

As you would have guessed, the third option is more viable for her though much harder to maintain. I recommend a moderate deficit, but for the sake of this example and Jess's wedding, we will look at the "large deficit."

So, 25% of a TDEE of 1900 is 475 calories.

So we take this number and minus it from Jessica's TDEE: 1900 - 475 = 1425 calories.

Therefore, Jessica must eat 1425 calories a day to be in a large deficit of 25%.

So at the end of 4 weeks, given a deficit of 7,700 calories equates roughly to a kilogram of body weight lost (2), Jessica would lose 1.7 kilograms, which will definitely be noticeable.

Whilst how we calculate the below macronutrients (protein, fat and carbohydrates) is beyond the scope of this article, Jessica's sensible diet approach would look like this:

Protein: 150 grams (600 calories)

Fat: 50 grams (450 calories)

Carbohydrates: 94 grams (376 calories)

Total = 1426 calories.

So if Jess sticks to this for a month, she'll lose roughly 1.7 kilos before the wedding. 

How long will it take me to lose "x" amount of weight?

How to lose weight without exercising

This is the most common question nutritionists face! 

Let's say, under the 25% daily deficit approach, Jessica wants to lose 4 kilos.

Given we know roughly that 7,700 calories equate to a kilogram of body fat, then 4 kilograms x 7,700 calories gives us 30,800 calories -- the cumulative deficit Jessica must achieve.

Under the 25% deficit Jessica is in (a 475 calorie deficit daily to be precise), we'd simply divide the required deficit of 30,800 calories by her daily deficit of 475.

This gives us 64.8 days, or 9.3 weeks, meaning that's how long it will take Jessica to lose 4 kilos.

But Jessica, just like you, must reduce her calorie intake as she goes. You can't keep eating the same amount of calories and expect to keep losing weight.

Moreover, given weight loss is more efficient when combined with exercise to create a calorie deficit (5), we need to be clever about how we keep readjusting our calories for fat loss.

And the best way to do this is, is when fat loss slows to below 0.5 kilos a week, you reduce your calorie intake further by 10% (6).

That way your fat loss won't stall, and you'll keep seeing fat loss results.

Whilst this ideology that a "7,700 calorie deficit equates to a lost kilogram of body fat" is sometimes seen as an oversimplification (3), it's still a strong yardstick for us to use when we keep dietary readjustments in mind. This is also because Jessica could experience some muscle loss, thus making the equation not totally accurate. But for the sake of simplicity, this is what weight-loss experts and nutritionists continue to use (2).

Research has always shown a 500 daily calorie deficit to be a good benchmark for fat loss (4), and this is why you hear that number thrown around as a rough guide when it comes to losing fat.

So, science and maths are clear: you CAN lose weight without exercise.

And by following the above steps, you'll do exactly that!

References

(1) McDonald, L. 2008. Body Recomposition: Setting the Deficit – Small, Moderate or Large.

(2) Hall KD. What is the required energy deficit per unit weight loss?. Int J Obes (Lond). 2008;32(3):573-576. doi:10.1038/sj.ijo.0803720

(3) McArdle WD. Exercise physiology: energy, nutrition, and human performance. 4th edition edn. Williams & Wilkins; Baltimore: 1996.

(4) Carels RA, Young KM, Coit C, Clayton AM, Spencer A, Hobbs M. Can following the caloric restriction recommendations from the Dietary Guidelines for Americans help individuals lose weight? Eat Behav. 2008 Aug;9(3):328-35. doi: 10.1016/j.eatbeh.2007.12.003. Epub 2008 Jan 4. PMID: 18549992.

(5) Redman, L.M. at al. 2009. Metabolic and behavioral compensations in response to caloric restriction: implications for the maintenance of weight loss. PloS One. Vol. 4, No. 2, e4377.

(6) McDonald, L. 2016. Alan Aragon Research Review (AARR): How to Adjust Your Diet for Continuous Fat Loss [online]. [viewed on January 17, 2017]