Calorie Restriction: What Are We Really Doing To Our Body?

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Calorie restriction is not a new thing in the weight loss world, it seems to be the number one way to lose weight- but what are we doing to our bodies when we take restriction to the extreme?

Let me first explain to you where this post has come from- why I have written it, what made me even look into calorie restriction and the effects of it in the first place. We're all friends here- right?

I wrote a post around three months ago admitting to some of the past behaviours I had been trying out in order to lose weight. It's called "I Thought I Was Doing It The Right Way.." and that title is linked if you want to have a read.
In that, I told you about my calorie counting and intermittent fasting, I spoke of being obsessed with what I was putting in my body and how I looked. I was in such a bad place, I had an unhealthy relationship with food and everything was about how I looked.
When I wrote the post I was coming out the other side, my relationship with food had improved greatly and I was feeling good. It was around a month after that post I fell back into the trap of counting calories. Tt was the pressure of the festive season and holidays coming up that I wanted to look and feel my best (which I thought was only determined by how I looked.)
I restricted my calories hard, telling myself I was just in a deficit as the girls on Instagram always put it, and while I was toning up, I was not losing any weight. I was stuck in pretty much the same weight I had been in for a month. I was tired all the time, and in the words of my boyfriend I looked "permanently ill".
I gave myself a break on holidays- the counting and restricting of calories stopped, the vigorous, punishing workouts every day stopped. I came home from holidays feeling better, and even looking better than I had in quite a while. I didn't look pale and tired and sick.
This post has come from that, from me realising I was restricting my calories too much for me to be healthy or to be seeing any positive changes in my body.

I saw a change in my body when I began eating more calories- and it really got me thinking, am I doing this completely wrong? What I am really doing to my body by not consuming enough calories? I've stopped counting and again and just simply making healthier choices with regards to food. However, I see it everyday on Facebook group- girls being unaware of the dangers of restricting calories. So I did the research for you.

Our body needs calories to function, they are responsible for helping out in three main, very important processes.
  • A certain amount of the calories you consume are used to digest and metabolise the foods we eat. This is called the thermic effect of food. 
  • A number of your calories are needed in order to sustain your basal metabolic rate (BMR). This covers all the basic functions of the body- the brain, the liver, the lungs, the heart, the nervous system ect. 
  • Calories also fuel your body with the energy it needs to get through your every day tasks and workouts.

Now that we have a general idea of what calories do- we can have a better understanding of what is happening to our bodies if we aren't getting enough of them.

  • Your body goes into starvation mode- this mean the body responds to the consumption of not enough calories by storing them instead of burning the. This doesn't happen overnight, instead it takes a long, drawn out process of continually not consuming enough of the calories that the body is in need of. According into Nutrition, Exercise, and Behaviour: An Integrated Approach to Weight Management by Liana Summerfield and Stephanie K. Ellis, when the body goes into starvation mode it can show symptoms such as the following: 
    • weakness and fatigue;
    • an intolerance to the cold;
    • an irregular menstrual cycle;
    • dizziness;
    • constipation;
    • swelling of the hands and feet. 

  • Your metabolism can be affected by a lack of calories as well. If you are regularly not consuming enough calories your metabolism can be slowed down. This effect of not enough calories is not an easy fix either, once the damage has been done it is quite hard to reverse, meaning that simply upping your calories will not fix it. It will persist for a long period of time after you begin eating at a maintain acne level again. In the research report by Michael Rosenbaum and Rudolph L Leibel titled Adaptive Thermogenis in Humans they stated that the effects on metabolism due to calorie restriction is to blame for more than 80% of people re-gaining the weight they lost through a calorie restrictive diet once they finish the diet. 

  • In women especially, continual restriction of calories can have an impact on fertility- why you ask? Because a womens ability to ovulate depends on her hormone levels which are effected by how many calories she is consuming. In a research paper written by Loucks AB, Verdun M and Heath EM in 1998 entitled Low Energy Availably  Not Stress of Exercising Alters LH Pulsatility in Exercising Women" they concluded that luteinising hormone or LH depended largely on the amount of calories consumed in the diet in order to increase the amount of the hormone and therefor have ovulation occur. A women who is eating 22-42% fewer calories than she actually needs for her body to be working optimally can suppress her reproductive functions. Oestrogen levels hay also be reduced by insufficient calories. 

  • Not enough calories can also lead to nutrient insufficiencies- obviously by not giving your body certain foods you are also not going tithe nutrients it needs to perform. 
    • Not enough iron, folate and vitamin b12 can have a huge effect on your fatigue. 
    • According to research lowering your carb intake can go one of two ways depending on the individual. In some it can make you extremely fatigued and run down, in the other corner it can have the opposite effect and instead reduce fatigue. 
    • Low levels of vitamin A can leave you with a weakened immune system and sometimes even permanent eye damage. 
    • Not fuelling your body with enough protein can result in muscle loss, thinning of the hair and brittle nails. 
    • Were you told as a kid that you needed to drink milk in order to have strong bones? Well they weren't wrong. Not giving yourself enough calcium an weaken your bones, making you more susceptible to fractures. 
    • Biotin and thiamine, two things you don't here about that often, but you don't get enough of them it can cause muscle weakness, hair loss and scaly skin. 
    • And finally, magnesium. A magnesium deficiency can lead to muscle cramps, abnormal heart rhythms, fatigue and migraines. 
I've told you of four ways that restricting your calories can have a negative effect on your body- but for each person there could be a hundred more. If you are thinking about entering a calorie deficit I have one recommendation for you: visit  and use their macro calculator to determine how many calories to cut out and how many to keep in.