Pexels valeria boltneva 1251198


What is "If It Fits Your Macros"?

by Tobias 6 minutes read

Last updated: 15 Dec, 2022

If It Fits Your Macros or IIFYM is a new diet that is taking over the world of weightlifting and bodybuilding, but can this way of eating help the average person maintain a healthy weight? Today, we find out.

What is IIFYM?

Before we look into what IIFYM is and how it works we have to explain a few definitions that the average person may not be aware of. For example, a "macro" is short for macronutrient. Protein, Carbohydrates and Fats are all referred to as macronutrients. As opposed to Vitamins and Minerals which are known as micronutrients. Alcohol is sometimes included as a macronutrient as it behaves differently in the body compared to the other three but for ease sake it's sometimes easier to just look at the ethanol content as a form of carb as it is "burned off" in a similar way.

IIFYM is often considered an extension of the CICO diet. CICO refers to "calories in, calories out". The basis of the diet is that the body can't distinguish between "high quality" and "low quality" food and instead treats a calorie as a calorie, regardless of its source. IIFYM continues this train of thought by breaking down all food and drink into their constituent macronutrient parts.

IIFYM is just that, you can eat whatever you'd like as long the macros fit within your set amount i.e. 120g of protein, 200g of carbs and 100g of fat. If your daily eating fits into that bracket then you have succeeded for the day. you can eat whatever you like as long as it fits your macros.

This way of eating can be very effective for those people that want a lot of flexibility in their diets as there is literally no food or drink that is not allowed. If you are someone that travels regularly or has to eat at times and places that you can't dictate, such as work events or social occasions then IIFYM could be very useful to maintain a healthy weight.

A key benefit of CICO and IIFYM is that whilst managing your macro intake you can actually adjust your body composition. If you want to want to gain weight and gain muscle then you need to increase your calories and up your protein intake. If you want to lose weight and body fat, you reduce your overall calorie intake, keep your protein intake high but reduce excess carbs and fats. Whatever your goals, there is a way to utilise this diet plan.

How to follow IIFYM

As mentioned previously, IIFYM is a continuation of CICO so the first step to following IIFYM is to follow CICO. If you've not already done so please take a look at our article all about CICO. The first step is to use a calorie calculator to work out your daily calories and your daily macro needs. This figure will vary depending on your age, gender, height, weight, your given activity level and your goal. Using all these variables the calculator will then give you the amount of calories, fats, carbohydrates and protein you should eat per day.

Then all you need to do is follow your macros calculation and keep a track of everything you eat and drink. There are several ways to do this, but the most common options are either to journal it using an old fashioned pen and paper or you can use a much more modern method to count macros by adding all of your food choices onto an app on your phone such as MyFitnessPal.

Remember to track your goals too, so if your goal is to lose or gain weight, i'd suggest you weigh yourself every week or two. Remember, always weigh yourself at the same time every day, my recommendation is as soon as you wake up, fit it into your normal routine but remember to weigh yourself before you get in the shower or eat anything.

By tracking your goals regularly you can track small changes in your body, so you can then increase or decrease your calories and adjust your macros to make sure you continue the progress. As you lose weight you will need to eat less and less to maintain that weight. Wait a couple of weeks between each adjustment to be sure that the adjustments you are making aren't just short term changes.

If you do hit a plateau after 2 or 3 months then don't be afraid to take a week off of tracking and eat intuitively. Chances are your body knows what it needs and you will find yourself craving foods that should. But don't take too long off or you could undo all of your hard work.

Once you have maintained a weight that you are happy with then my suggestion would be to keep tracking food for a week or two without aiming for any particular levels. This will give you an indication of how your body will change when eating intuitively. Once you are happy with where you are physically then you can slowly reduce the amount of food you track until you can stop altogether. You can always go back to tracking your food if you start to drift from your goals.

Pexels narda yescas 1566837

Note - we NEVER suggest putting strawberries on a pizza


There really are so many benefits when comparing the IIFYM diet to any other diet. The first of which is that there are no limiting and structured meal plans to follow. There really is no limit to what you can eat, if it fits your macros.

The IIFYM way of eating is easily adjustable. The calculator above isn't exactly correct for each person so if you aren't seeing the changes in body weight that you had hoped then just adjust the macros. Remember not to change your macros too frequently or you won't be sure if you are seeing long term results.


Of course, as with any way of eating there are downsides and limitations. Because of the need to track everything you eat and drink this could lead to obsessive behaviour and disordered eating in some people. Please tell your friends and loved ones before undertaking this diet as they will likely be the first people who will notice this behaviour.

The amount of freedom given in this way of eating is a double-edged sword. You can eat whatever you like, good or bad. Regardless of what your health goals are, any sensible person would know that it is not healthy eating 100% of your calories from bacon. As tempting as that may be. There is a certain amount of self-policing that each person needs to do when undertaking this diet.

Overall, IIFYM can be a very beneficial way of eating, giving you complete control over what you eat and when. The science backs it up, as long as you stick within the macro goal, and aim to eat a balanced diet, you can find positive results eating whatever you please.

We aim to always give appropriate credit to our reference sources and image authors. Contact us if you think a credit may be incorrect or you're an author and would like to request removal.