I Don’t Make The Rules – Biology Makes The Rules

In my previous post, How Calories “Work“, I said

“So if you are convinced you are that one special snowflake who is accurately tracking 1500 calories and working out 2 hours a day and still gaining weight: YOU ARE NOT. You really really are not.

You are not eating 1500 calories and gaining weight. 1500 calories will ultimately maintain (barely) 100 lbs in a full grown sedentary woman. This is truth.”

I got a few comments and messages that were in opposition to this concept. They were mostly polite, which I very much appreciate. Some argued that they were different from most people and need fewer calories, others argued that they had tracked very accurately and they really did gain weight on 1500 calories, or they partly agreed with me except for where they gain weight if they TRY to set a very low calorie range.

In essence, they boiled down to this:

“So yes, at 1500 calories,  I do gain weight.”

For any person with a weight above what 1500 calories maintains (around 100 lbs): at a true 1500 calorie intake, you cannot gain weight.

I don’t make the rules, biology makes the rules.

You cannot gain weight (fat or lean mass) in an energy deficit. If your energy intake (calories) are far below your energy expenditure (TDEE), you will lose weight. If your TDEE is above 1500 calories (and believe me, it is) you will not gain weight eating 1500 calories, because you are bringing in less energy than you are using.

You can temporarily store a little extra water, but that is a response to stress hormones from starvation, in the case of extreme restriction (which is what a 1500 calorie diet is – extreme restriction, starvation). So for a day or two, with a strict 1500 calorie intake, you might have a slight increase in water weight, but it won’t last.

But we are talking about a longer period of time, which is when you would see a loss. It would be unavoidable, if you were starving, to lose weight. That’s how it works. I don’t make the rules, biology makes the rules.


An example: you track your intake, you try to keep it at 1500 calories. If your TDEE is 2500 calories, you have created an energy deficit of 1000 calories. You are, theoretically, burning 1000 calories MORE than you are feeding your body. And as far as your body knows, you are starving it.

Your body responds to starvation in several ways. This is where things get a little “interesting”.

One way is by an increase in stress hormones (cortisol, adrenaline), to keep your energy up for a few days … SO YOU CAN FIND FOOD. When that doesn’t happen, and calories don’t increase, your energy will drop.

Another way is by reducing your burn rate (“metabolism”) slightly: so you use a little less energy at rest.

By reducing your non exercise activity thermogenesis (NEAT): you do less fidgeting & incidental non-exercise activity, so you burn even fewer calories.

One other thing your body can do: put you in kind of an “autopilot” state about eating, so you will eat food without being entirely aware of how it impacts your caloric intake. Caloric under-reporting is a well-known phenomenon. (http://www.bmj.com/content/311/7011/986)

Caloric under-reporting: when I say “without you being entirely aware”, I do not necessarily mean you are eating while sleepwalking (although that can happen!) – I mean that you will do things like forget to track a handful of nuts or a latte’, or stand at the kitchen counter eating a box of crackers without noticing. In essence, you will be grazing and seeking out food, without being consciously aware of how it ties into your daily calorie intake. If you are not fully aware of a handful here or a sip there, you won’t track it. This is incredibly common. Reputable diet & nutrition studies do not rely upon only self-reported intake, for this reason. Most people are unreliable reporters. We just don’t remember every morsel of food, this is NORMAL. Add to that, calorie counts for foods (whether packaged, home made, or restaurant prepared) are notoriously difficult to estimate with any kind of accuracy.

Reactive overeating (or reactive bingeing) is what happens when you set a caloric intake for yourself that is so low that your body truly rebels against starvation when food is actually available. You may eat enough food to wipe out the deficit you’ve created with your diet, and ultimately then eat so far above your TDEE that you actually gain weight – all while being only semi-aware of your actual eating behavior, and being certain you are “only eating 1500 calories”. You might even develop a regular habit of “binge nights” or “cheat days” that bring your caloric intake up to and above your TDEE very quickly.

(Reactive bingeing or overeating is a response to extreme caloric restriction – it should not be confused with Binge Eating Disorder, a recognized mental health condition. I am not qualified to assess the difference for you. If you think you may have Binge Eating Disorder, please reach out for professional help! You deserve to be happy and healthy – YOU MATTER.  http://www.edreferral.com/.)


“But I was really accurate and I really am gaining weight on only 1500 calories!”

Please know I am not dismissing your experience or your frustration!

You are right, in the sense that in trying to starve yourself you may have gained weight. But the weight gain is not because of the 1500 calorie intake – it’s because of TRYING to have a 1500 calorie intake. Do you see the difference?

Your brain is trying to starve your body. Your body wants to protect itself, it wants to preserve itself. It will rebel, and one of the ways it rebels is by sort of shutting off your conscious awareness of your food intake. After all, your conscious brain is the organ that is trying to starve it.


Take a good look at whether what you’re doing now is actually working. Consider whether eating enough food to support your activity, health, and happiness seems like a logical step in the right direction.

Start by giving yourself permission to eat ENOUGH.

If you give yourself permission to eat ENOUGH food, your body and mind can work together. Your body can do what it is designed to do: move, breathe, sleep, protect your incredible brain & heart. Your mind can rest, and think, and create, and plan – without struggling through hunger.

You are amazing, you are awesome, you are beautiful, you are strong: you deserve to eat enough food to be able to fuel all of that and more, for a long, long time.

What is ENOUGH? It’s more than 1500 calories, for sure. It may be more than 2000 calories, or more than 2500 calories, it depends on your body & your activity. Start with the TDEE calculator, see how much energy it takes to actually live your life every day.

Start with ENOUGH. See how that feels for a while.

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