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Trigger Warning: Calories In:Calories Out. If you know that this is a lie, this post really isn't for you and I respectfully suggest you not read any further.
A calorie is a measure of energy contained in food. Calories are calculated now by adding up the macros contained in the food, explored macros here. There is one universal truth about calories, if you don't have enough from your food, you will lose weight and eventually die. The opposite of losing weight is gaining weight, whether it's muscle or fat it still requires energy. Energy is never created or destroyed, it's just converted into a different form of energy. How this looks in food is:
Sun => Plants => Cow => People > (maintenance+movement+growth)
The sun radiates solar energy which is absorbed by plants. The plant is eaten by the cow which turns the energy contained in the plant into movement, muscle and fat. The cow is eaten and the energy from the cow is used by people for movement, muscle and fat. In this chain, plants harvest energy from the sun, cows are mobile factories concentrating the energy into beef products. Of course, vegetarians and vegans would skip the cow part and eat the plants directly.
Whatever you eat, energy from food is converted into the many chemical reactions and electrical impulses which happen automatically in your body. These events describe your metabolic system or metabolism which we will investigate in detail later. Energy is also used to create muscle and fat. Both of these tissues require energy to synthesis, you cannot create something out of nothing. If you eat more energy than your body requires, it will be stored as fat. To avoid this storage process, you can increase the energy demands from your body by performing movement or reduce the amount of energy entering your body.
In order to lose weight, you have to make sure that your body gets less energy from food than it requires. If this happens, then in order to stay alive, your body will start to use energy stored as muscle and fat. If energy consumed is not sufficient you will eventually run out of internal energy stores and die. There is no 'Starvation Mode' to prevent this. This is not a negotiable process and it doesn't matter how healthy, organic, cleansing or gluten free your diet is, food is energy and that energy will be used or stored. You cannot eat more food to lose weight, it might make you feel better but there is no 'hack' or magic potion/pill or super food that will make you lose weight. No Bariatrics Consultant will ever recommend eating more to lose weight and neither will any Endocrinologist or Cardiovascular consultant. It's telling that all the surgical interventions to lose weight involve making calories less available to the body whether it's through a bypass surgery or making the stomach smaller. If you suspect that you can't lose weight because of a medical condition, please see your GP to have this treated.
So how do I know how much energy my body needs and how much energy there is in food?! There are two numbers you need to know, your BMR and your TDEE.
Your BMR is your Basal Metabolic Rate. This number is the number of calories each day which your body needs to maintain it's weight if all you do is lie in bed resting. Click here to calculate your BMR.
Your TDEE is your Total Daily Energy Expenditure. This is how many calories your body needs each day to maintain it's weight taking into account your BMR and your activity levels. Click here to calculate your TDEE.
Now that you know these two numbers, you'll need some way to know how much energy is in your food. There's two things which will be very helpful: food scales and a tracking App like MyFitnessPal. Personally I use MyFitnessPal because it's very easy to use and there's an inbuilt bar-code reader which you can use to scan your food label. Previously, we discussed the importance of Tracking so if you know what your numbers are and act accordingly then guaranteed you will achieve your Goal.
If you eat more than your TDEE, you will gain weight and if you eat less, then you will lose weight. As you lose or gain weight, your BMR will constantly decrease or increase because more size requires more energy/less size requires less energy. In turn this will affect your TDEE.
You might be surprised at how little or how many calories you actually need to maintain your current weight. Averages like 2k for women and 2.5k for men are hugely misleading. Because there's a set amount of processes which occur within the human body, when you calculate your BMR, it will be very accurate to within a hundred calories of your resting energy demands.
Once you have these numbers what are you going to do with them? Depending on what your goal is perhaps you might start by eating -200 calories or +200 calories of your TDEE. Monitor this for a week and adjust as necessary. Your BMR might be accurate but your TDEE will vary a lot depending on your perception of activity. Note, if you indicate that you have a very active lifestyle, don't then add any extra calories you burn from an app such as Strava or your FitBit. You have already accounted for your extra activity level and you don't want to double count your required calories!
How did your BMR and TDEE come out? Surprised? Let me know what you think. Next post, we'll combine everything we know from this post about calories and the previous post about food content.
If you are unsure if this will affect your health adversely, please speak to your GP or a qualified Dietician. Do not confuse a Dietician with a Nutritionist. The word 'Dietician' is a protected by law and to be a Dietician you need to be registered Health and Care Professions Council (HCPC)
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In this nutrition series:
The information contained in this blog does not constitute medical advice and is not intended to counter advice provided by a licensed medical professional. If you have a health problem, please seek help from your GP and not from the internet. Our Medical Information Disclaimer may be found >here.<