We need to make adjustments to our calorie intake as we diet if we’re to be successful with our fat loss goals. This is because a calorie and macro calculator can only give estimations, and our energy needs change over time due to various compensatory mechanisms.
Weight fluctuations often mask fat loss, so it can be hard to know when to adjust. This is something most people are completely ignorant of, slashing calories when weight loss stalls and failing their diets because they can’t sustain it.
We want to remain eating as much as possible for as long as possible, and we want to make those cuts from the macros in the least compromising way.
To know when (and when not) to make adjustments, it’s essential to understand first why you need to make adjustments, why fluctuations in weight and appearance happen, and how to track your progress so that you have the right data to interpret.
The key from there is to give yourself a rule framework so that you don’t get impatient and do stupid shit.
Why Your Initial Calorie and Macro Calculations Are Only Estimations
“But the calorie and macro calculator says I should be losing weight!!”
Incorrect. The calorie and macro calculator, as with any calculator, is merely a tool to help you estimate what your intake should be for your goals. Additionally, our energy needs change over time due to various compensatory mechanisms.
There are three key parts of your calorie intake calculation. Your basal metabolic rate (BMR), an activity multiplier, and the adjustment to create the calorie deficit needed to lose weight at the rate you are targeting. The equation looks like this:
Target Daily Calorie Intake = BMR * Activity Multiplier – Calorie Deficit Needed
The BMR component of this is an estimate based on group averages. There are simple formulas and very sophisticated formulas, but they all give estimations based on group averages.
The activity multiplier is an estimate based on how active you are. There is a subjective component to this. No amount of explanations can help get around that; trying to rely on activity trackers to estimate, given their inaccuracies, is not the answer.
We have little choice but to use an initial calculation knowing that it may need to be adjusted, track our progress, and then adjust based on the outcome. This is what I do with all clients and you cannot deny that it works well.
Metabolic Adaptation — Why Our Energy Needs Decrease As We Diet
Calorie balance is what determines whether we lose or gain weight. The ‘problem’ is that energy intake affects energy expenditure. This is called metabolic adaptation.
There are particularly strong protective mechanisms designed to keep us alive during times of famine, which is why it’s easier to get fat than it is shredded lean.
It requires a 3500 kcal energy deficit to lose 1 lb of fat (7700 kcal for 1 kg). This ‘3500 calorie rule’ is often criticized because it is sometimes stated without acknowledging that our energy needs change as we diet. If this weren’t the case, all currently-weight-stable Thelma would need to do is cut out her morning frappushittino™ to end up skinny.
But we know it doesn’t work that way. What starts out as a calorie deficit, is eventually eroded away.
Let’s take a look at the components of Total daily energy expenditure (TDEE)
- Basal metabolic rate (BMR) is our resting energy expenditure (REE) and makes up the largest component of our total daily energy needs.
As we get smaller, our BMR drops because there is less of us to maintain. However, the BMR drops further than what the tissue losses alone would predict, due to a compensatory mechanism called adaptive thermogenesis. Thyroid hormone levels decrease and mitochondrial efficiency increases, reducing energy expenditure.
- Non-exercise activity thermogenesis (NEAT) is a posh name for energy used during “non-exercise” movement, such as fidgeting or normal daily activities. This also decreases when we diet. It happens more for some people than others.
- The thermic effect of food (TEF) is the energy used to ingest, absorb, metabolize, and store nutrients from food. As we eat less, this decreases also.
- Exercise activity thermogenesis (EAT) is a posh name for the energy used during exercise. The lighter we get, the less energy we expend.
Because there are differences from person to person, it’s not possible to calculate the level of metabolic adaptation we will have, we just have to track our progress and adjust things along the way.
Am I Metabolically Damaged?
In short, no. Hormonal issues requiring medication do exist, but it’s unlikely that you have dieted your way into one.
This is a concept born out of desperation for people to explain their lack of progress when dieting. But it can be explained by three things:
- People think a single calculation at the start of a diet can predict progress through to the desired result. But as I’ve just explained, this is not true.
- Underestimating calorie intake and overestimating energy expenditure. This is well documented in the scientific literature.
- Water retention and sudden whooshes can mask fat loss. This is especially common during periods of high stress (and for women over their monthly cycle) and is something people aren’t aware of. (More on this in the next section.)
There are two other important responses to a sustained caloric deficit worth highlighting: increases in ghrelin and decreases in leptin. These two hormones are, broadly speaking, responsible for hunger and satiety.
So whenever someone says, “Hey, I’m eating only 1200 kcal and I’m not losing weight! What am I doing wrong?!”
The chances are that they’re underestimating calorie intake (whether through incorrect logging or their calorie calculator lying to them), or they are losing fat but they have some water retention, or the way they are tracking progress is inadequate to conclude that progress isn’t happening. (I’ll come back to this later).
When you factor in that shorter people have lower energy needs in a world with large portion sizes, it’s natural for this misery to be compounded and for life to not seem fair. (It isn’t.)
The reality is that we just have to eat less and less to keep progressing as we diet. And at the same time, hunger increases, satiety decreases, and this sucks. This is why we need to be smart about the adjustments we make and not slash calories needlessly.
Thank you for reading. This was a sample chapter from my book, The Diet Adjustments Manual 📙.
Questions are welcomed in the comments and I answer daily.
If you haven’t read my free Nutrition Setup Guide yet 📖, download it by entering your email address in the box immediately below. 👇