There is SO much information out there about nutrition! Some of it true, some of it not, some of it true for some people, some of it very biased. It can be so hard to know what to trust and what will work best for you but I hope I can help a little..! I want to cut out all opinions and theories and give you a simple, no-nonsense guide to nutrition. After years of my own research and experimentation, here is the science true for almost everyone in simple, practical terms.
A calorie deficit
In simple terms, regardless of what type of food you eat, if you eat less calories than you burn then you’ll lose weight and if you eat more than you burn then you’ll gain weight. Of course, if you only eat sugary, fast food there will be other health consequences but this fact still remains the same.
Your calories in are very simply just from what you eat and drink but the calories you burn can be slightly more complicated. You will burn a certain amount of calories just by being alive each day which will be different based on your gender, height, weight and metabolism. This is called your basal metabolic rate (BMR). It’s very hard to accurately guess this without experimenting for a while but a good equation to start with is: 655.1 + (weight in pounds x 4.35) + (height in inches x 4.7) – (age x 4.7).
Then you have any calories you burn through exercise but also your non-exercise activity thermogenesis (NEAT) which is any activity you do that’s not a workout like climbing the stairs, walking to the train station, standing up. To get a general idea of these calories, multiply your BMR by a number based on your activity level. Here’s a guideline:
Sedentary/ no exercise X1.2
Moderately active/ workout 3-5 times a week X1.5
Super active/ workout everyday/ very physical job X1.9
(You can go somewhere in between these numbers if you feel your activity level is between them)
This will give you your maintenance calories or the calories you should eat to stay the same weight. Again I’m going to say it, this is an approximation and everyone will vary slightly so you will need to try it out and change it to suit you!
Then very simply, if you want to lose some weight then cut your calories by 10-20% and if you want to gain weight then up them by 10-20%.
As an example, I will show you my numbers!
655.1 + (121 x 4.35) + (62 x 4.7) – (23 x 4.7) = 1364.75 kcal
And I am pretty active so I will multiply it by 1.6 giving me a maintenance of 2183.6. To go in a deficit and lose weight I’d drop it down to about 1750 and to gain weight I’d go up to about 2600.
Now I know in practise these numbers are a bit high and my maintenance is actually about 1800. This is probably because my body has got used to being more active and also because I did under-eat for many years so my body adapted to living off much fewer calories at that time.
There are 3 macronutrients- carbohydrates, protein and fat. Technically alcohol is a 4th macronutrient but I wouldn’t recommend giving a daily percentage to this! You’ve probably heard of diets that completely cut out carbs or fat and these may work for some people but I strongly believe everyone can reach their peak health while eating a balance of all 3 and will definitely be more sustainable!
Carbohydrates are our bodies main source of energy, especially during exercise so you can see why they are important! If you are constantly tired then not eating enough carbs may be a cause of this. Carbs come in the form of sugar, starch and fibre. Sugar gives fast releasing spikes of energy whereas starch provides a slow releasing energy throughout the day.
I have never heard of a diet that advises you to cut out protein however there are a lot of conflicting ideas about how much you need. I’ve heard numbers of anything from 0.5g to 2g per kg of bodyweight. Especially on the upper end of this, you can imagine how someone overweight could end up with an impossibly high amount of protein to eat! For this reason, using your lean body mass can definitely be a better tool. If you know your body fat percentage then just take this off your weight so I weigh 55kg and am about 25% body fat so that leaves me with about 41kg of lean body mass. Then multiply this by 2.2 for an estimate of how much protein you should aim for. Protein is essential for growth and repair of the body and especially the building and repairing of muscles so is especially important after exercise.
Fat is perhaps the most demonised macronutrient. Yes, too much fat can raise cholesterol and lead to heart disease but having some fat in your diet is essential! Fats helps absorb some vitamins, support heart health, aid proper function of the brain and nerves and can be a source of energy. It’s important to recognise the difference between saturated and unsaturated fats- I’ve linked below a helpful NHS article if you need a bit more information on this! Per gram, fats have more than double the number of calories than carbs and protein so you can start to understand why you need much less fat.
So how much of each should I eat?
I’ve said it before and I will say it again.. this will completely vary person to person and you will need to experiment to find out what works for you! I’ve linked below the iifym website which has a great calculator tool to work out a good starting point for your calories and macros. It takes into account your gender, age, height and weight, body fat percentage, activity level and your weight goal and is definitely the best tool I’ve found online for this. Alternatively, you could use the tools I gave above to work out you calories and protein intake and then choose your fat and carbohydrates around this. Another way would be to simply track what you already eat in an average day just to see. If you feel tired then maybe you need to up your calories or carbs or if you’re struggling to build muscle or recover after training then you could try upping your protein.
Carbohydrates and protein have 4 calories per gram and fats have 9 calories per gram so once you have your calories and percentages planned, you can use this to work out how many grams of each macronutrient you need. Just for reference, I will share my plan at the moment. I am currently training for a slight cut whilst maintaining as much muscle as I can and I am a pretty small human so my calories are lower than most people!
50% Carbohydrates (213g)
25% Protein (107g)
25% Fat (47g)
Micronutrients are the vitamins and minerals you get from the food you eat. These don’t really effect the calories or macronutrients in your diet but are essential to allow your body to function healthily. The average person shouldn’t need to take supplements and eating a good variety of fruits and vegetables should be enough! I’m not going to go into a lot of detail but I will link a good article at the bottom if you want to learn more.
Tracking vs Intuition
I have done both tracking every calorie and macro I eat everyday and tracking nothing for months and there are definitely pros to both. I will just say, if you have ever had a history of eating disorders or restrictive eating then it could be very unhealthy or triggering to track your food and you can eat just as healthily without doing so!
If you are very new to nutrition then I would recommend tracking at least for a while so you can learn about the calories and macros in certain foods and meals and get a better understanding of what you eat. If you are used to eating unhealthily then you will likely crave unhealthy foods and so intuitively listening to your body might be dangerous! If you are training for a specific goal like entering a competition or losing weight for a wedding or holiday in a set amount of time then tracking could help you keep on track.
On the other hand, I wouldn’t recommend tracking everyday forever! It can be easy to become obsessive or miss out on social events because you’re worried about not hitting your macros. Once you’ve tracked for a while, you will probably find that you can eyeball what’s in a meal pretty easily. You will likely know what you need to eat to hit your protein goal and if you eat a higher fat breakfast you will probably be aware of that and be able to adjust the rest of your meals accordingly. Also, once you’ve been eating healthily for a while and created new habits, you might find you start craving healthy foods and so listening to your body about when you’re hungry and what foods you want can be pretty healthy and reliable!
I would recommend finding an in between that works for you! I track what I’m eating maybe one day a week so I can see if I am hitting my goals and if there is anything I want to change but I would then make those changes intuitively over the rest of the week. If you’ve never made a meal before and you don’t know how many calories or what macros are in it then you might find it useful to put all the ingredients into an app to work that out so you can change the quantities to fit your goals better. Even when I am tracking, I just use it as a guide and wouldn’t not eat the meal I had planned just because I’d go 100 calories over my goal!
I would always recommend My Fitness Pal for tracking and the free version is definitely good enough! You can put in your calorie and macronutrient goals, track all your food and it will show you a summary throughout the day of the foods you’ve eaten and the remaining calories and grams of macronutrients you have in your goal.