Diet and nutrition

Thomas Rothwell, lead physiologist at AXA Health

How to lose weight well: creating a calorie deficit

Diet and Nutrition

8 August 2019

How to lose weight well

AXA Health lead physiologist, Tom Rothwell, explains the basic science behind an age-old question: what is the secret to fat loss? Clue: the answer doesn’t lie in detox tea (or ‘teatoxing’), detox pills, or fasting, nor does it lie in ‘compensating’ for what you’ve eaten by doing a hard session in the gym.

Tom explains:

In an age where #ripped, #gains and #shredded are the hashtags du jour on many social media platforms, it’s easy to get swept up in the frenzy about what’s right, wrong, or hot right now in the quest for the holy grail of weight loss.

It’s no wonder this is still a misunderstood topic in society, as we are inundated with fad diets, supplements and self-proclaimed ‘gurus’ claiming they can solve all your problems when it comes to losing fat. What many of these avenues fail to do is to educate and empower us on the topic of fat loss. 

Weight loss v fat loss

‘I want to lose weight’ is the goal we often set ourselves but, more often than not, we really mean ‘I want to lose fat’. Our weight can fluctuate throughout the day; this can be due to many things, such as hormones, acute food/water intake, carbohydrate intake, the previous day’s food intake and salt intake, to name a few. This is the reason why weight on the scales is not necessarily the best indicator of fat loss or gain.

Considering around 60% of our body weight is water, solely focusing on scale weight to look at fat loss or gain is pointless and potentially damaging in some cases if we then start to rely on and become obsessed with the numbers we see. Better methods would be a body fat percentage test (if you have access) or invest in a tape measure.

Circumference measurements of your waist (use your belly button as a reference point), thigh or upper arm are useful measures to check progress. Not only is the waist measure great to track progress in area that we might be conscious of, it is really important regarding health. Typically, a larger waist can indicate greater fat stores around stomach, otherwise known as visceral fat. Excess visceral fat is linked with an increased risk of diabetes and cardiovascular disease so, by tracking your waist measurements, you might even get an insight to what’s going on inside your body, not just how you look.

Don’t forget that underwear sizes, clothes sizes, belt sizes, how your clothes feel on you and progress photos are all useful tools, too!

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The science behind fat loss

The body is a complex system with many interlinking parts and, when it comes to fat loss, it’s no different. But there is one thing that you need to have if you are to lose fat ahead of anything else, and that's a ‘calorie deficit’.

What is a Calorie Deficit?

A calorie deficit is when we expend more energy than we intake.

‘Calories in’ is simply the calories we intake through food and drink. ‘Calories out’ is a little more complex, and is made up of three things:

  • Basal Metabolic Rate (BMR) – Energy needed for all automatic and natural processes that occur in the body, for example, breathing.

  • Physical Activity Expenditure (PAE) – Energy expended through exercise (and even when we don’t feel as though we’re exercising, e.g. walking, commuting, gardening, etc.).

  • Thermic Effect of Food (TEF) – Energy needed for us to digest, absorb and metabolise food.

The government dietary recommendations on how many calories the population should aim to consume in a day to maintain a healthy weight is 2,000 for women and 2,500 for men. This is a rough guide and largely depends on how active you are (your physical activity expenditure).

It’s easier to create that calorie deficit through altering our food intake than it is to try and out run a ‘bad’ diet, but that’s not to say there isn’t a role for exercise in weight loss – there absolutely is and with it comes a whole host of other benefits, like heart health, brain health, improved mood, not to mention self-esteem and body confidence. But for fat loss, it’s easier to manipulate what we’re eating, rather than trying to out exercise excessive calorie consumption.

What should I do, then?

There is no ‘one size fits all’ approach when it comes to losing fat – as individuals we’re all physiologically different and what works for a friend may not work for you. But there are two things that should be at the forefront of your mind when making food choices:

1) Is it a way of eating that you enjoy and can stick too? Food is there to be enjoyed, not dreaded, or to feel guilty about.

2) Is it creating a calorie deficit?

Generally, we tend to exclude all the foods we enjoy when fat loss is the goal. But you can include these ‘enjoyment’ type foods into your diet if you are still creating that deficit. Ultimately, this will help you adhere to a specific way of eating long term because you’re not denying yourself anything and therefore less likely to binge. You don’t always need to count calories for weight loss, although they are important; simply keeping an eye on your portion sizes goes along way. More often than not, we tend to underestimate how many calories we eat on a daily basis. This is where keeping a food diary with the number of calories can be useful in highlighting a few areas where you could make slightly better food choices. Alongside your progress in body measurements, you can then start making adjustments to your calories.

As for how many calories you should drop in a day to create a deficit, this is very individual and depends on a number of factors, such as how much fat you want to lose, your metabolism, if you have a medical condition, or your age. A general rule of thumb is creating a deficit of around 500 calories a day, but it really does depend on the person. Some may feel their energy levels decline, while others may feel fine. Recording how you feel in a food diary, noting down your energy levels, mood, feelings of hunger or tiredness are useful clues to gauge whether the deficit might be too much.

If your weight or waist measurements aren’t decreasing, then you’re not in a calorie deficit - that’s why keeping a food diary is such a good idea to track what you’re eating.

Key takeaways

  • Try not to focus solely on scale weight to track progress.

  • Eating foods you enjoy will make healthy lifestyle choices easier to stick to in the long term.  Our article on intuitive eating covers this in more detail.

  • Manipulating our food intake is the most effective way to create a calorie deficit and lose fat –  exercise can help but it’s extremely difficult to out run a bad diet.

  • It can take time, so try to be patient, nourish your body, move more, and enjoy the journey.

Most popular diets have one thing in common, regardless of the method: they try to create a calorie deficit. This can mean we often end up skipping meals or eating food we might not enjoy, leaving us undernourished, irritable and hungry. Try to design a balanced diet that works around you and your life, as opposed to following something you don’t enjoy.

You may be interested in

Intuitive eating - AXA Health

Energy boosting foods – AXA Health

Super salads – AXA Health

Diet and nutrition centre – AXA Health

Exercise and fitness centre - AXA Health

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