How much food should I eat in a day? A guide to tracking your macros

How much food should I eat in a day? A guide to tracking your macros

Learning how much food that I needed to eat changed my life. Yes you read that correctly. It changed my life, and my body too.

By learning how much food to eat in a day I started to get results from my training in the gym. I started to appreciate food rather than fear it. I saw food for what it is rather than classify it as fattening or safe to eat. My hormones sorted their shit out. I finally learnt how to respect my body instead of punish it. And you can too!

It begins with learning how to track you macros.

It might sound difficult to begin with….yes there are some calculations involved and you will need to weigh your food. But, I promise you that the little bit of effort it takes to get the hang of tracking your macros is SO worthwhile.

What is tracking your macros? 

I feel like no matter what I write here you are going to think that this is just calorie counting and it doesn’t work for you. Macro tracking is counting how much protein, fat and carbohydrates, as well as how many calories, you eat each day.

It is next level calorie counting but this time it will work for you!

Let me explain why:

– This kind of calorie counting determines your calories based on your body and goals (rather than a generic calorie number)

– Counting protein as well ensures you lose mostly body fat, not muscle as well

– Tracking properly and consistently overtime allows you to make adjustments to your calories and macros to help you continue getting results

It is the only way to truly learn how much food you should eat in a day.

Where do I start?

We are going to break up the process into two parts:

A. Calculating your macros

B. Learning how to track them accurately

A. How to calculate your macros

To make this as easy as possible I’ll break it down into 3 steps. Also, I’ll show you how I’d calculate my macros so you can see how it’s done.

Note that there are a lot of variables that come into play when doing this. I’m going to show you the science and for the sake of not writing a book, leave out most of the art. These are just starting guidelines. You will have to adjust your macros, especially as you progress.


To start, find the amount of calories you need each day to maintain your current body weight. This is your total daily energy expenditure (TDEE).

There are many ways you can do this. If you are already tracking your food then you can simply see how much you are eating daily and then assess how this lines up with your progress. If you know you are eating 2000 calories a day and your body weight is fairly stable week by week then you know your maintenance is 2000 calories.

If you are not already tracking you can use the Katch-McArdle equation to work out your BMR and then multiply this by an activity multiplier to get your TDEE.

Katch-McArdle Equation:

BMR= 370 + (21.6 x Lean Body Mass (kg) )

To get your lean body mass, multiply your body weight in kg by your body fat percentage and then subtract this number from your body weight. If you don’t know your body fat percentage you can google body fat percentage images and then compare yourself to one of the photos to get a fairly good estimate.

Activity Multipliers:

1.1 = Very Inactive
1.2 = Mostly Sedentary
1.3 = Active
1.4 = Intense Training
1.5 = Extremely Active / Athlete


My BMR would be: 370 + (21.6 x 43.7) = 1313.92

My TDEE would be: 1313.92 x 1.3 = 1708 calories

(Note that I chose ‘active’ as my activity multiplier and I workout 4 days a week as well as go for two 30 min walks daily)


Now we will use the calories from Step 1 and factor in your goal to see how much food you should eat for this goal.

You’ll likely have one of three goals: to lose fat, to build muscle or to maintain your current body weight.

To maintain simply use the calorie number you got in Step 1.

To lose fat you want to create a calorie deficit. Usually this is anywhere from 15%-30%. The faster you want to lose fat, the greater the deficit required but the harder it is going to be to adhere to this. 

To build muscle you want to create a calorie surplus. The greater the surplus, the more fat you are likely to gain as well as muscle. The range of the surplus is usually 5%-15%.


Let’s say I want to lose some fat and I don’t have a deadline. I am going to choose a conservative deficit of 15%.

This means my fat loss calories will be = 1708 x 15% = 256

1708- 256 = 1452 calories per day


This is where you figure out whether you can eat the whole donut or just half. In science words, you’ll calculate the number of grams of protein, fat and carbs you need from the calorie target you estimated in Step 2.

Protein is necessary for building and repairing muscle and plays a structural role in your body. It will also help you stay fuller for longer. You want to make sure you are hitting your protein target! Protein has 4 calories per gram (you will need to know that for the final part of the calculation).

Your protein target should be in the following ranges:

Fat Loss protein= 0.8-1.3 grams per pound of lean body mass

Muscle Gain protein= 0.8-1.1 grams per pound of lean body mass

Note that it is per pound of lean body mass rather than bodyweight!

Next up is fat! You need a specific amount of fat for things like hormone production, cell membrane integrity and energy storage. Fat has 9 calories per gram.

Your fat target should be in the following ranges:

Fat Loss Fat= 0.25-0.5 grams per pound of bodyweight

Muscle Gain Fat= 0.25-0.5 grams per pound of bodyweight

Finally the remaining calories will come from carbs which, although not essential to the body, provide energy and help with your performance in the gym. Plus they are delish! Carbs have 4 calories per gram.

It is good to make sure they balance out the fat macros and fit within the following ranges:

Fat Loss Carbs: 0.5-2 grams per pound of bodyweight

Muscle Gain Carbs: 1-3 grams per pound of bodyweight

For example if you like eating carbs then you can choose a number on the higher side of the range but this means that your fats will be on the lower end of the range.


Let’s say I want to go with 1.3 grams protein because I want to maintain as much lean body mass as possible. I prefer carbs to fats so I’ll stick to the lower end of the range of 0.3 grams per pound of body weight for fat as this will allow my carbs to be higher.

So PROTEIN= 1.3 x 96.34 (this is my lean body mass in pounds) = 125 grams

FAT= 0.3 x 123 (this is my body weight in pounds) = 37 grams

Now to figure out how many calories left for carbs:

Protein cals used= 125 x 4 = 500 cals

Fat cals used= 37 x 9 = 333 cals

Calories left for carbs= 1452- 500- 333 = 619 cals

CARBOHYDRATES= 619 / 4 = 154 grams 

IN SUMMARY, my fat loss macros would be:  125 Protein, 37 Fat and 154 Carbs

Note: This is a starting point! Consistent adherence to your macros needs to be combined with your progress data in order to benefit from tracking macros.

B. How to track your macros

Now for the fun part! Once you have your macros you can start tracking them.

For this you will need to download a food diary app and buy a digital food scale. Then start practising!

The most common food diary app is My Fitness Pal but if you are based in Australia and have an iPhone then I recommend Easy Diet Diary as it has more Australian brands in the database. To track, all you need to do is weigh your portion of food, search for it in the app and then enter the number of grams of that food you weighed out. For example, say you wanted to log a smoothie… You would just put the blender on a scale, press zero, then add 200 grams of milk and log that, then add 30 grams of protein powder and log that, then add 100 grams of raspberries and log that. If you are out at a cafe, then just log what you know is in the smoothie, and estimate portion sizes used. The more you weigh things out at home, the better you will get at estimating when eating out.

Tips for weighing your food:

– weigh foods like meat, pasta, rice and potato raw if possible (you can put a bowl on the scale, press tare to make it zero and then add raw food before cooking it).

– for sticky things like peanut butter you can put the jar on the scale and then zero it. Then spoon out as much as you like and the negative number on the scale will be the weight of peanut butter on your spoon.

– always use digital scales to measure food because cup measurements are inaccurate.

Tips for hitting your macros:

– practise!

– enter the meals you want to eat first and then add in everything else. If you know you are going out for pizza then you would put that in first and work around it.

– it can help to log all your food at the start of the day and make sure it all fits before you eat anything.

– start by hitting your calorie and protein target first and then once you are used to that you can hit your fat and carbs too.

– it can be hard to be spot on so aim to be as close as possible in the range of +/- 3-5 grams for each macro.


A: If you go over any or all of your macros then don’t stress, just try to hit them better the next day.

A: Yes and no. Unless you are a total beginner to the gym I would focus on one or the other. If you need to do both and you are not a beginner, most people prefer to lose fat first and then build up muscle but it really depends on how lean you are to start with.

A: A lot of people will tell you that counting calories or macros may make you obsessive and causes eating disorders. I disagree and I had an eating disorder. Everyone is different but I believe that learning how to track my macros was the biggest thing that allowed me to recover properly. I do not fear food anymore, no matter what it is or how much I eat, because I know how my body responds. I am not going to get fat overnight. I also don’t need to binge eat anymore. I can fit treats in everyday so that they no longer phase me. If I feel like one I’ll have one but they aren’t a reward for getting to the weekend and they aren’t something I crave like crazy either. They are neutral.

A: I recommend eating home for as much as you can for the first week of tracking to get a better idea of what portion sizes look like. Then you will find tracking food when eating out a lot easier.

A: Remember knowledge is power! Knowing how much food your body needs opens up the door to intuitive eating.

It is so hard to intuitively know what you need to eat when we have been bombarded with mixed advice from our parents, schools, the media and our friends since forever. You might not even realise how much of an influence this has on your food choices and eating behaviours!

Tracking your macros allows you to make better judgements of being hungry and gives you peace of mind that you are eating enough of the right types of food to reach your goal.

A: Pretty much. The idea around flexible dieting is that so long as you stick to your macro targets you can eat more flexibly that what you can on a typical restrictive diet. I still recommend trying to get 80% of your diet from whole food sources and the other 20% can be whatever fits, including treats if that is what makes you happy.

A: Technically alcohol is its own macronutrient but for the purposes of macro tracking you can count it as a carb or a fat. So say you had 100grams of wine and logged it as 100grams of wine, it would show up as added calories but it would not contribute any carbs or fat or protein. You need to add this manually to your carb or fat total. You can do this by dividing the total number of calories of the wine by 4 if it is going to count as a carb, or 9 if it is going to count as a fat.

A: For best results I recommend tracking macros alongside following a proper weight training program that is also based around your goals. 

A: By measuring progress! I’m writing an article on how to do this soon!