If It Fits Your Macros IIFYM –The Optimal Guide to Flexible Dieting

If you have started to care about your diet and your health you’ve most probably come across articles or videos talking about “If It Fits Your Marcos (IIFYM). Actually, this form of eating has its own website where they bring up the possibility to eat junk food while getting leaner.

But is eating everything you desire the ultimate goal of IIFYM philosophy or is it just an excuse to indulge in junk food?

Let’s find out.

How does it work?

IIFYM is a form of eating based on tracking your caloric intakes instead of focusing on a “one-size fits all approach”. It’s relatively “new” as a popular dieting ideology in the fitness world and bodybuilders have been doing this flexible dieting approach for a long time already.

IIFYM focuses on meeting daily macronutrients targets and not specific meals to reach your objectives. So instead of just tracking your calories, which lacks structure, IIFYM diet gives you specific macronutrients goals to reach per day which in total equals the number of calories required for you to lose fat or build muscles. You are then allowed to eat whatever you want as long as your caloric goals and macronutrients (I will explain what they are shortly) objectives are reached. It’s a form of eating that relies on science and on the principle that not a specific food will make you fat. You feed your body to tailor specific metabolic demands as long as “It Fits Your Macros” which are macronutrients requirements.

What are macronutrients?

Macronutrients are any of the three basic nutritional components of diets such as carbohydrates (carbs), fats (lipids) and proteins. Each one of these macronutrients provide energy to the body in form of calories. For instance, carbs and protein contain 4 calories per gram while fats have 9 calories per gram.

In other words, when you look at a and it says the food contains 12g of carbs, 8g of proteins and 0g of fats, this food has 80 calories.

With flexible dieting, you plan your meals with a certain amount of protein, carbs and fats based on your fitness goal (lose fat or build muscle). You still have to count your calories and use a bit of basic algebra.

For example, if I want to lose fat, I usually eat around 2000 calories per day. These 2000 calories are broken down in 180g of protein, 195g of carbs and 55g of fats. As you can start to see it’s a form of calorie counting. Now, you might have been used to read about how certain foods contain so much calories and you need to avoid them. Well, as long as you hit your macronutrients target for the day, the foods I eat won’t affect my body composition negatively.

Sounds unbelievable right? But it’s science. As long as I hit my macros goals, I will either lose fat or build muscles.

Look at the following example:

440 calories, 24g protein, 56g carbs, 16g fats in 2 slices of Hawaiian pizza


440 calories, 24g protein, 56g carbs, 16g fats derived from tuna with brown rice and olive oil.

I know it sounds crazy… Is it too good to be true?

Is the IIFYM diet effective?

YES! It is a way of eating that makes your life easier and help you achieve your goals if you apply the principles correctly. Let’s talk about how it works.

Even at rest your body burns energy each day, and it is measured in calories. A calorie is the amount of energy required to heat up one kilogram of water one degree Celsius. Your body is an efficient machine and turns food into calories regardless of where it comes from.

Do you see some people regularly eating junk food and candy without gaining weight? It’s not only about their metabolism. As long as your body burns more energy that it receives, weight loss will occur. There have been several experiments where a person eats junk food every day and is still able to lose weight. Remember that we are talking strictly about losing weight and not fat so far.

This is the reason why the diet is called “If It Fits Your Macros” because the goal is not only to count calories but also to track your macronutrients. It’s a for more superior way of dieting since this approach takes into account body composition.

When you go on a caloric deficit you will lose weight. This decrease in weight could be a reduction in fat as well as water or muscle mass. In order to avoid losing muscle mass you will need to get enough protein per day while you apply stress to your muscles in order to make them grow (by weightlifting or calisthenics). A certain level of fats is required for hormone synthesis and you need enough carbohydrates as a source of energy and to provide your muscles with glycogen while exercising.

This way of eating is extremely interesting for bodybuilders and athletes since we experience different cycles between intense training before a competition and off season. While you might lose and gain weight throughout the year you don’t want to lose too much of your muscle mass in the process. Additionally, what one eats in order to reach his/her macronutrients targets is not key to this diet approach. Carbs coming from pasta, bread or candy will be turned into glucose just like carbs coming from green vegetables or brown bread. Proteins from hamburgers are still made of amino acids chains as well as fresh tuna.

Well, this would be just so easy to think that way. After all, is food only fuel for your body or is there more to it than just macronutrients?

Make great gains at the gym while eating unhealthy food? It’s delusional

Food is not only fuel for your body. It is more than that. The body needs micronutrients such as vitamins and minerals to function properly. Most junk and processed foods lack these micronutrients. Additionally, the added ingredients and sauces that make the food taste good are mostly empty calories (they are not nutrient dense). Having a “cleaner” diet provides your body with enough micronutrients and will help you feel more satiated.

Regularly eating junk food has been associated with vitamins deficiencies and cause various type of health problem (chronic disease, diabetes, cancer and more). Plus, you will weaken your overall immune system and be more prone to catch viruses. So, it is a wiser decision to keep this kind of food in moderation. You could technically still eat junk food and get an impressive physique, but your immune system and overall health will be messed up. Always put health first.

How should I use IIFYM and how do I count my macros?

As I mentioned earlier in this post, I believe flexible dieting is an extremely good approach to reach your fitness goals. I personally add the following principles to make it work:

  • 80-90% of the daily calories should come from healthy food
  • If you decide to indulge, be reasonable and always aim for the healthiest option
  • 10g of fiber per 1000 calories
  • Avoid trans fats as much as possible
  • No meal timing necessary as long as you hit your daily macronutrients goals

Of courses there are some basic good habits that make you reach your goals such as eating more green vegetables (“more volume”). You won’t feel like you are dieting, and you will definitely feel fuller than if you decide to hit your carbohydrates target solely with starches for instance. You still have to adopt a “clean eating” approach most of the time if you want to hit your macros goals regularly. Calories from processed and junk foods add up quite fast.

People who will benefit the most from IIFYM are those you are unaware of what they are eating and those who have issue eating chicken and steamed veggies every day. When you don’t enjoy your diet, you become more prone to binge eating and give up. You either make excuses for not sticking to your meal plan or you feel bad and binge eat. In other words, you don’t have a plan for when you make mistakes or need to improvise. This is why flexible dieting makes your life much easier. With IIFYM, you are able to replace certain foods such as pasta for a bowl of oatmeal, eat your meals whenever you want, and you can also fit some of your favorite treats in moderation.

You can play around, eat whenever you feel like it, skip breakfast, have most of your meals in the evening etc. It’s a good experience.

As long as you focus on eating healthy micronutrients rich foods first you are free and feel more confident adding your favorite treats. It might take some personal investment for you to make sure you track quantities properly. Remain persistent, honest with yourself and allow some room for mistakes so you can understand what works best for you.

For example, I love eating cereals at night before going to sleep. Instead of eating my cereals with regular milk I use a cup of skim milk, so I get some protein intake without adding fats. I also like dark chocolate from time to time so I include it into my diet while choosing a healthy version of the dark chocolate (85% cacao). To the extreme, I allow myself to get ice cream of junk food while out with my friends, but I do it in a controlled manner. I plan the rest of my meals, so the junk food has less impact on my daily caloric needs.

This is the best way to make IIFYM and flexible dieting work for you. I eat 90% clean foods and I’ll have a treat here and there. There is no “cheat meal” in IIFYM philosophy. Everything is under control.

To track your calories, you can use an app such as MyFitnessPal. It is extremely popular and reliable. It tracks your steps, you can add your exercises for the day and your water intake. There is a also a supportive community around the app, and regular blog articles with recipes and tips to reach your goals.

It’s a good idea to make your own calculation regarding your calorie intake and MyFitnessPal make it easy for you to understand your macronutrients breakdown for the day. You can plan your diet, play around and experiment. Say you will go out clubbing with friends, then you can decide to include your alcohol intake in the app and play around to see what meals you are able to eat before going out (or after) in order to be able to reach your macronutrients needs. There is nothing complicated. A few minutes a day should be sufficient. Also, I recommend investing in a kitchen scale, it will make your life easier. When you weigh your carbs such as rice and pasta, use the uncooked weight always. You can use the cooked rice and pasta weight to make your meal preparation easier.

Is IIFYM the right diet for you?

It will most probably work for you. You should at least give it a try. You will get a good understanding of macronutrients, body composition and nutrition.

It’s possible that it won’t work for some people. Some folks like to eat the same foods every day and stick to a meal plan. I personally believe you should build a strong discipline first and commit to eat strictly clean foods for a couple of weeks. Once you build the discipline and see the benefits of clean foods for your body (improved digestion, increase of energy) you won’t feel like going back to junk food. You might want to loosen up from time to time so you can enjoy your social life since it might be difficult to have all your entourage eating solely clean foods.

The right diet is the one that works for you. Though, I believe that IIFYM covers most diet out there. You can be Vegan, follow a Keto or Paleo, even intermittent fasting and still take a flexible dieting approach. It’s highly compatible with IIFYM philosophy.

Conclusion/bottom line on IIFYM

I am definitely not telling you to binge-eat pizza and soda because it fits your macro. As long as your diet is based around healthy food and you exercise regularly, there is no reason not to include some chocolate or pastries here and there as long as it’s compatible with your macronutrient’s goals. Tracking your macros and caloric requirements works and makes your life easier. With a little bit of common sense and an effort to base your diet around healthy foods at least 80% of the time, eating your favorite slice of pizza or cake won’t affect your body composition.

Understand that you are building a lifestyle and not a diet to lose weight fast. Ensure sufficient intake of fiber (it will make you feel fuller) minerals and vitamins. Your success depends on your ability to remain consistent and reach your goals every day.

Also, more importantly, your long-term health is superior than reaching your macronutrient goals. It is compatible of course but make sure that your diet matches your goals and give you sufficient energy.

With that said, enjoy the foods you crave with moderation (if you crave green veggies: lucky you!) while reaching your fitness and health goals.

Published by

The Fit French

Hey guys! My name is Christophe and welcome to my blog. Here you will find articles to help you improve your fitness and nutrition.

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