Calorie Deficit To Lose Weight: Understanding The Energy Balance

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Simon Long

Simon Long

Simon is a highly experienced personal trainer and behavioural psychology expert
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If you watch my videos and read my blog then you may have heard me talk about the key requirement of any weight loss goal. That’s right, calorie deficit! Today we’re going to talk about what a calorie deficit is, issues with them and how to create them. We’re going to talk energy balance!

What is energy balance?

Simply put your energy balance is maths. It’s looks like this:

Calories In – Calories Out = Weight Loss/Maintenance/Gain

It’s the most important factor in deciding whether your weight reduces. It also impacts every other function in your body. Your metabolism, hormone function, enzyme function, mood and sexual drive (Bom chika wa wa!!)

To clarify. If you eat the same number of calories you burn during a day, then your weight doesn’t change. If you eat more calories than you need in a day, then your weight increases (due to insulin hammering the extra energy into cells. Like adipocytes, where fat’s stored). If you eat less calories then you burn then you lose weight (due to the body breaking down energy containing body tissues, such as triglycerides in fat cells).

So simple. You just eat way less calories and a few months later strut your stuff on the beach. Right? Well……

Issues around calorie deficits

The problem with calorie deficits is that they are incredibly hard to calculate. From both sides of the equation.

Calories in is not as simple as everybody thinks. You unfortunately cannot just enter your foods into your chosen calorie counter and hey presto. There are just too many factors that effect it. These include accuracy of portion sizes, consistency with logging, personal factors affecting how you metabolise food and inaccuracies in the reported number of calories in foods.

Calories out is even harder to work out. It is governed by NEAT (fidgeting), NEPA (non-exercise physical activity), thyroid function, individual enzyme and hormone activity, exercise, at rest calorie requirements, atmospheric and body heat etc etc etc. The list goes on and on. With all of these factors, even if we had you in the lab strapped to every machine we’ve got, we still couldn’t provide you with completely accurate number of how many calories that Zumba class burnt.

All of these issues with working out calories in and calories out result in more (or less) calories being eaten and burnt then reported. And even a small 10% difference can result in half a pounds’ worth of weight loss difference. Per week! Possibly more! And with the vast issues around calculating, 10% is probably a conservative estimate.

How to create a negative energy balance

So we now know that for weight loss we need a negative energy balance. We also know that creating this negative balance is difficult. So what do we do??

Well instead of intensely monitoring how many calories you eat and exercise, take a look at the whole picture. As with everything I preach, this is the only way to make weight loss not only successful, but sustainable.

Step one is to consider not only how much you eat, but what you eat. 100 calories of lemon drizzle cake is not the same as 100 calories of salmon. They will have different effects on your body. The salmon will have a higher thermic effect (how much energy is required to process food). The lemon drizzle cake will have a higher insulin effect (spiking and then crashing your blood sugar).

The first point may well require you to address your attitude towards food. So you’ll have to consider your mental approach and reasoning. Do you comfort eat when you are stressed or upset? Do you binge eat? Why do you do this? What is causing your stress?

Finally, you need to consider your physical activity. Training consistency is an obvious one. If your skipping workouts often then you are losing out on a large stimulus (Although if your skipping for the latest Netflix series then ok, you get a pass from me). But there is a lot more to consider around your training. If your workouts are focused on increasing muscle you will increase your bodies daily energy need. Your using high intensity interval training? Awesome. Then your increasing your post workout calorie burn. Do you mix up your routine to keep your body guessing or provide it with the same stimulus every time?

But don’t forget, physical activity is far more than just exercise. What you do for the rest of the day has a much larger impact on your energy expenditure. If you are physically active, then it can account for 50% of your calorie burn per day. If you sit around a lot, then it could be as low as 15%.

This activity can be absolutely anything. Standing up more, walking more, fidgeting when you are sat down and holding your shopping bags away from your side will all increase the energy burn of your body. Resulting in a larger calorie deficit.


So there you go. You now know:

  1. What a negative energy balance
  2. Why creating a calorie deficit can be hard.
  3. The best way to approach the problem.

As always if you have any questions around this, or ideas for future articles and videos, then just get in touch.

I hope you’re having an awesome day!

See you tomorrow,