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Why maintenance is a moving target (why fat gets ‘stubborn’)

Eating for fat loss is relatively straight-forward. Establish your maintenance calories and create a sustainable calorie deficit. The size of the deficit will determine how difficult it is to adhere to, but our recommendation would be a daily 550 calorie deficit (resulting in half a kilo of fat loss per week).

So for an individual whose maintenance calories are 2900, that would mean a daily calorie target to begin with of 2350.

The important words here, though, are ‘to begin with’.

Because this number will change as fat loss progresses.

Many people will report a fat loss plateau and don’t understand why things have come to a stop. The reason is simple: they are no longer in a deficit. How can this be?

What used to be ‘maintenance’ is now a surplus

It’s because maintenance is a moving target. There are a number of factors which affect maintenance including:

1)       Total bodyweight
2)       Total muscle mass
3)       Exercise
4)       Non-exercise activity thermogenesis (or ‘NEAT’)

1) Assuming no change in muscle mass, less fat means we are going to end up lighter. Someone who’s very overweight and ends up 10-20kg lighter from fat-loss will see a significant reduction in their maintenance calories.

2) Whilst it is something we try to avoid, most people lose some muscle when dieting. Muscle is calorically ‘expensive’ to the body, in that it burns calories at rest as it requires oxygen and energy to function. If a significant amount of muscle is lost when dieting, this will also serve to reduce our maintenance calories.

3) It should be possible to maintain (or even increase) the level of exercise as we lose fat. That way we can guarantee, providing we are working at the same intensity to the same level, during those sessions we will burn roughly the same number of calories.

4) Our non-exercise activity (NEAT) however is likely to fall significantly when dieting, and it is this component that people do not account for or are even aware of.

After 12 weeks of deficit we subconsciously move less so ‘maintenance’ falls further

NEAT refers to the calories we burn day to day from non-sport-like activities. For example, walking to the train station, typing at a computer, fidgeting etc. NEAT makes up the largest component of our non-resting energy expenditure, and so changes in this play a big part in determining if your initial deficit is still a deficit many weeks into your diet.

Studies show that NEAT is regulated by energy balance – it increases with overfeeding and decreases with underfeeding. Whilst your initial calorie target may facilitate half a kilo of fat loss per week, this is based on the level of NEAT you had when you started your diet – therefore most likely when you were over-eating and putting on weight.

After 12 weeks of being in a calorie deficit, we are naturally going to be more lethargic and less active in a non-exercise-specific way. Whether aware of them or not, most people make choices that preserve energy, such as taking the lift instead of the stairs. This also extends to subconscious activities such as fidgeting in our sleep. This is something we can’t control, but nevertheless causes a reduction in overall calorie burn.

Reductions in NEAT, overall bodyweight and (perhaps) muscle mass can nullify the deficit we created at the start of a diet. Our old deficit is now our new maintenance. Bummer!

The only way is to increase expenditure from areas we can control (exercise), or decrease our calorie intake, or a combination of the two. The method you employ will depend on how low your calories already are and whether you can afford to reduce them further whilst still maintaining adequate macronutrient and micronutrient intakes.

Rob Webster
Bodyscan Consultant