Why You Need to Eat More to Lose More

We’ve all been there – a new popular diet turns up with people singing its praises about how much weight they’re losing, so you give it a go. You follow the plan to the letter, dropping your calorie intake to very low levels. For the first few weeks, it’s great! The number on the scales goes down quickly, but then your progress slows down. You get lots of cravings and eventually give in and you end up back at square one. 

So what happened? 

It’s become alarmingly common, despite all the advice saying otherwise, for news outlets, celebrity endorsements, etc to claim that eating very low levels of calories is the answer to losing weight. Be it just restricting calories every day or following a branded diet plan, they all follow the same pattern. If you hear anyone suggesting a diet where on any day you drop below 1000 calories, red flags should be popping up all over the shop. 

Let’s take the 5:2 Diet, for example. The idea is simple – five days of the week, you eat whatever you want, but on two days you fast, consuming just 500 calories a day. This is concerning for me and many other fitness professionals, for reasons I’ll go into below.

Now here’s the thing, and something I briefly touched on in my last article. There’s a certain level of calorie intake that’s essential for your body to function properly. If you remained completely motionless, your body would still need this level to keep your organs, immune system, etc, working. This level is called your Basal Metabolic Rate. It’s also worth noting that BMR doesn’t take into account the digestion of food. So with that in mind here are some things to bear in mind when considering food intake: 

BMR – Basal Metabolic Rate: the number of calories your body needs to maintain vital organs and body systems. For the average person this takes up to ~70% of your daily energy needs. (To easily calculate your BMR and avoid nasty equations, click here).

TEF – Thermic Effect of Food: the energy required to digest your food. Typically this is about ~10% of your daily energy needs. 

Activity Levels: here’s where it varies. Everyone has different levels of activity, so therefore the energy expenditure will differ. A more inactive person may find their energy requirements for day-to-day life is ~10%, whereas a very active person may find theirs is ~30%. If in doubt, take the average of ~20%. 

So to work out what your body actually needs day-to-day, we just need to add these together. Let’s use me, as an example. My activity levels are generally high, so I’ll take 30% as my activity value, making my BMR 60% of my daily needs and TEF remains at 10%. As my BMR is 1815 kcal (using the link above), my TEF is therefore 302.5 kcal and my activity requirements are 907.5 kcal. Added together, that makes 3025 kcal per day. 

Let that sink in. For my activity levels I require 3025 kcal per day for maintenance. Even if we were to take your average man and woman in the UK at the age of 25, using 20% for activity, the totals come out at 2491.5 kcal and 1960.75 kcal respectively. 

So that should put into perspective why going below 1000 calories per day is an extreme thing. And it makes sense, right? Weight loss equals more calories burned than consumed, right? Yes, but regularly going too far below your body’s needs means your body enters ‘starvation mode’. 

Your body is a clever, yet also irritating thing. When deprived of nutrition for too long it begins to prepare itself for potentially not getting much food again. This means your metabolism gets wiped out, so your body gets less efficient at processing the food you eat. More of that food then gets stored as fat in preparation for the long time your body thinks it will be going without food. What this ultimately results in is that you will find your energy levels dropping, cravings increasing and mood souring. When you eventually and inevitably overeat to compensate, from your body forcing you to eat, your weight will just climb back up to where you started from, maybe even higher. Keeping an efficient metabolism running helps you digest food properly and prevent fat storage – and an easy way to boost your metabolism? Eat regularly and plentifully. Another way of thinking about it: all of your bodily functions that help you to burn fat require energy. Without that energy intake, your fat burning potential drops and muscle mass will also drop in order to pick up the slack. 

You cannot rush things. A far better and sustainable plan would be to calculate what your intake should be (based on numbers or listening to your body) and then adjusting by a little bit either side to achieve your goals. If you want help with this, get in touch – I'll happily lend a hand. 

So at the end of the day, calorie restrictive diets don’t work. They won’t do what you want them to in the long run and they’ll make you tired and hangry. 

What are your thoughts? Have you had experience of a crash diet? Let me know in the comments below?