Does IIFYM Work For Weight Loss (Step-By-Step Guide)

These days it can be difficult to figure out what diet is going to work best for you in order to lose weight because there are so many different options out there. IIFYM is known for its flexibility because no food is ‘off-limits.’  But many people wonder if a diet can work for weight loss without any restrictions.

So, does IIFYM work for weight loss? Yes, because the IIFYM approach not only controls your caloric intake but ensures the right amount of macronutrients are being consumed for your body type and activity level.  IIFYM is also easy to sustain long term. Any diet implemented over the long-term will help you lose weight.

As a nutritionist, I’ve used this approach for many years and have led countless clients to success with their weight loss goal using IIFYM.

In this article, I’m going to break it down for you step-by-step.

Here’s what you’ll learn:

  • What is IIFYM?

  • What are macros?

  • How does IIFYM work for weight loss?

  • How to figure out your macros for weight loss?

  • How to track your macros for IIFYM?

  • What about vitamins and minerals?

  • Other helpful tips for weight loss

Let’s get started.

What Is IIFYM (If It Fits Your Macros)?


What is IIFYM?

What is IIFYM?

IIFYM, or ‘If It Fits Your Macros,’ is a flexible dieting principle that helps people lose or gain weight without being restricted from eating certain food items.

If you’re following the IIFYM approach, you will calculate how many grams of each macronutrient (protein, carbohydrates, and fats) you need to eat each day to reach your weight loss goals.

Then, you’ll track your food intake to make sure you meet those macro goals.  What you eat per se doesn’t necessarily take priority over hitting your macro goal for the day.

For example, let’s say you calculate that you need to eat 150g protein, 150g carbohydrates, and 70g fats in order to lose weight.

If you ate pancakes with syrup for breakfast, the meal would contain something like 5g protein, 50g carbs, and 10g fats.  The macros from that meal would then be subtracted from your overall daily macro goal.

So while other weight-loss diets might say you can’t eat pancakes and syrup, with the IIFYM approach you’re allowed to eat whatever you want so long as you’re sticking to your daily macros.

Before we get into why IIFYM works for weight loss or how to calculate your macros for weight loss, we need to understand what the macronutrients are.

Note: If you already know what macros are, feel free to scroll to the next section.  You may also be interested in how to plan your workouts while cutting.

What Are Macros?

Macronutrients (aka macros) are energy-producing nutrients. Energy producing means that they contain calories.

Calories are made up of the three macronutrients: proteins, carbohydrates, and fats.

When following the IIFYM diet, you’ll be tracking these macronutrients.

Once a macronutrient is consumed, it converts into energy for your body to use.

  • Protein and carbohydrates produce the same amount of energy on average, at 4 calories per gram.

  • Fat has more than double the number of calories that are present in protein and carbohydrates at an average of 9 calories per gram.

Let’s take a closer look at each macronutrient.

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PROTEIN


Proteins are one of the macronutrients in IIFYM

Proteins are one of the macronutrients in IIFYM

Protein is a component of every cell in your body and is used by the body to repair tissues. It is a principal component of bones, muscles, cartilage, skin, and blood.

Where is it found?

Some sources of protein are meat (poultry, beef, pork), fish (white fish), egg whites, dairy products (greek yogurt, cottage cheese), tofu and other soy products, as well as protein supplements.

Other food items, such as beans, nuts, and vegetables, also contain protein but it is not the main macronutrient.

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CARBOHYDRATES


Carbohydrates are one of the macronutrients in IIFYM

Carbohydrates are one of the macronutrients in IIFYM

Carbohydrates are the body’s main source of energy, fuelling the majority of brain’s activities as well as providing a significant portion of the energy our muscles and other tissues in the body need to thrive.

Where is it found?

Fruits, sugar, candy, soft drinks, pasta, potatoes, bread, rice, oats, beans, vegetables, and flour are common carbohydrate sources. It is more common to find products that derive the majority of calories from carbohydrates.

That being said, there are many carbohydrate sources that also provide a significant amount of protein such as beans, grains (i.e. quinoa) and some vegetables.

As you can see, there is almost always some overlap between food sources and their macronutrients.

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FATS


Fats are one of the macronutrients for IIFYM

Fats are one of the macronutrients for IIFYM

Fat is an essential nutrient that our bodies require to live. It assists in vitamin absorption, hormone regulation, brain function, providing energy, insulating against temperature extremes and maintaining cell membranes.

Where is it found?

There are few foods that are only comprised of fats, these would be items such as oil and butter.

Items that derive the majority of their calories from fats are nuts, seeds, and nut butter.

Other sources of fat are often high in protein as well, such as meats (beef, pork, dark poultry), fatty fish (salmon, tuna, trout) and eggs.  Dairy is also a common source of fat, such as cheese and full-fat milk, cream and yogurts.

So now that we know what the macros are that are involved in the IIFYM approach, how can we be sure that this strategy will work for weight loss?

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How Does IIFYM Work For Weight Loss?


A calorie deficit will lead to weight loss

A calorie deficit will lead to weight loss

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CALORIC DEFICIT

The concept that makes up the basis of any diet is what we call energy balance. 

The results you get are dependant on calories in versus calories out.

  • Maintaining your body weight:  If the amount of calories you are taking in is the same as the amount that you are burning, your body will be maintaining the amount of fat and muscle that is present and you will be in energy balance.

  • Increasing your body weight:  If you are taking in more calories than you are burning in a day, you will be in a caloric surplus that will lead to muscle and/or fat gain.

  • Decreasing your body weight:  If you are burning more calories than you are taking in on a daily basis, you will be in a caloric deficit that will lead to fat and/or muscle loss.

Here’s the key formula for any diet:  It will work if it puts you in a caloric deficit.

Since we now understand that calories are made up of the three macronutrients, it makes sense that by tracking your macros with an IIFYM diet you are also controlling your caloric intake.

Therefore,  you can ensure you are in a caloric deficit in order to lose weight.

So then why wouldn’t we just count our calories and not bother with counting the macronutrients?

This is a great question and something my clients ask me all of the time.

The different macronutrients perform various functions when they are consumed and affect weight gain and weight loss in different ways.

Let’s take a closer look.

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PROTEIN & WEIGHT LOSS

Protein is required for building and protecting our muscles. Adequate protein intake is also a vital aspect of a fat-loss diet as it plays a vital role in controlling our appetite and providing your body with the feeling of being full.

When protein is being digested and reaches the small intestine, a hormone is released (cholecystokinin) which slows the digestion process down in order for the nutrient to be properly absorbed.  Because it is slow digesting, it makes us feel full, keeps us satiated for longer, and therefore reduces the want or need to eat more than is necessary.

Adequate protein intake is also a necessary component of a diet where one is trying to lean out because protein is essential for the rebuilding of muscles.

When we are working out, our muscles are put under stress in order to break them down so they can repair and rebuild to be bigger and stronger. Without adequate protein for our muscles to feed on, there would be no materials to rebuild the muscles.

When we have more muscle, our body burns more calories in a resting state which can assist in burning fat. Therefore it can be understood that adequate amounts of protein is vital for both fat loss and muscle gain.

To summarize, by tracking our macros using IIFYM, we can understand how consuming the right amount of protein can help with weight loss in the following ways:

  • Build muscle 

  • Burn fat

  • Keeps us feeling full and satiated, reducing the want or need to overeat

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CARBOHYDRATES AND FAT LOSS

Carbohydrates are used by our bodies as a form of energy.

Any surplus that isn’t needed immediately is stored in the cells as glycogen.  Glycogen is a form of energy storage and when energy is needed, glycogen is broken down further into glucose which is a quick and easily accessible form of energy for the body.

If the body has sufficient amounts of energy, it may reach its storage capacity for glycogen. The liver converts the stored carbohydrates into fats so that the excess energy can be transported to the fat cells for longer-term storage.

This is obviously not what we want on a weight loss diet.

Therefore, eating properly portioned carbohydrates when following an IIFYM approach can be effective in producing the right amount of energy at the right intervals without storing fat and thus be effective for weight loss.

To summarize, by tracking our macros using IIFYM, we can un
derstand how consuming the right amount of carbs can help with weight loss in the following ways:

  • Only consuming what our body needs for energy

  • Not over-consuming what will be turned into fat

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FAT AND WEIGHT LOSS

The body breaks down fat after it is consumed so it can pass into the bloodstream and then either burn it as fuel or store it for energy in the future. Much like carbohydrates.

However, the body is not able to store as much energy in the form of carbohydrates, so much more of it is converted and stored as fat.

The fat that is stored is used when food is lacking and energy is required. The body can store much more fat than it can carbohydrates, making it a more efficient form of energy when it isn’t required immediately.

Fats are extremely important for proper body function, muscle gain and weight loss. They are the building blocks of our hormones, cell membranes, and nervous system.  If these systems aren’t being fuelled by enough fats, it will be extremely difficult to build muscle and burn fat.

As well, since they provide more energy per gram (remember, 1g of fat provides 9 calories), they are key in suppressing hunger, so you can see why we’d want a healthy amount of them in our diet if our goal is weight loss.

To summarize, by tracking our macros using IIFYM, we can understand how consuming the right amount of fats can help with weight loss in the following ways

  • Maintain sufficient energy levels

  • Keep hormones working efficiently (to help us sleep, build muscle and burn fat)

  • Suppress hunger 

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FLEXIBILITY WITH NO “OFF LIMIT” FOOD

On IIFYM, there are no foods that are off-limits.

As long as they fit into your macros, you can have them.

This is a great way to promote balance in your diet and develop a positive relationship with food. Research shows that restrictions in a diet can increase cravings and ultimately lead to overindulgence and ‘cheating’ on your diet, which will reduce the likelihood of any successful weight loss strategy.

Additionally, restricting certain foods or food groups has been shown to induce feelings of guilt, anxiety, and depression – not feelings conducive to successful weight loss.

By having the freedom to choose whatever you want to eat, the experience will be more enjoyable, and thus sustainable for a longer period of time compared to a restrictive diet.

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How to Figure Out Your Macros For Weight Loss (5 steps)


5 steps to figure out your macros for weight loss

5 steps to figure out your macros for weight loss

The first step to get started with an IIFYM diet is to calculate your daily macronutrient targets.

1. CALCULATE TOTAL DAILY ENERGY EXPENDITURE (TDEE)

In order to know how many calories you need to consume to reach your goals, you need to know how many calories you burn in a day, on average.

This is called your total daily energy expenditure, or TDEE.

There are a few different ways to calculate your theoretical TDEE, the easiest being to input your personal stats into an online calculator like this one.

2. SET CALORIES

If your goal is weight loss, you’ll want to reduce your TDEE by 10-25% to begin with. This will put you in a 10-25% caloric deficit.

One way to know where to start would be to track the calories of a typical day of eating for you before starting IIFYM.  If that number is much lower than your TDEE, you can start at a deficit of 25%.

However, if your current intake is above your current TDEE, you’ll want to take a more gradual approach to avoid shocking your system and causing potential hormonal dysregulation. If this is the case, a 10% deficit is the most you’ll want to begin in.

Note: If you’re wondering how to track your calories, it’s super easy.  I will explain in the next section.

Let’s go through some examples:

  • If you calculate your TDEE to be 2500 calories, you’ll want to start off anywhere between 1875 and 2250 calories.

  • If you track your current caloric intake and estimate you are currently only consuming 2000 calories, then you should start out at 1875 calories.

  • If you track your current caloric intake and estimate you are currently consuming 3000 calories, you’ll want to start out at 2250 calories.

Great, now we know how many calories we want to consume. Let’s figure out the macros.

3. SET PROTEIN

Depending on your level of activity, you’ll want to start by setting your protein intake at 1 – 1.25g of protein per lb of bodyweight.

  • For example, if you are someone who weighs 200lbs and goes to the gym 1-3 times per week, you’ll want to set your protein at 200g.

  • If you are someone who weighs 200lbs and goes to the gym 5-6 times per week and performs an intense activity, you’ll want to set your protein at 250g.

4. SET CARBOHYDRATES

When deciding how much carbohydrates you want to consume in a day, it’s important to understand how efficient our body is going to be at utilizing carbohydrates.

This is largely determined by our activity level. The more active we are, the more efficient our body will be at using carbs as energy, rather than storing them as body fat.

For someone who is very active, such as an elite-level athlete, you would want your carbohydrate intake to be around 40% of your total caloric intake.

  • So if you’ve set your calories to 2000, for a highly active person that would mean 200g of carbohydrates.

For someone who is not very active at all, maybe who goes for a walk 2-3 times per week and that’s it, you would want your carbohydrate intake around 25%.

  • So if you’ve set your calories to 2000 and are a very inactive person, that would mean 125g of carbohydrates.

For those who fall somewhere in the middle, who work out at the gym at a moderate intensity 4-6 times a week, you’ll be looking at 30-35% carbohydrates.

5. SET FATS

Fats are extremely important for proper body function. They are the building blocks of our hormones, cell membranes, and nervous system.  If these systems aren’t being fuelled by enough fats, it will be extremely difficult to build burn fat.

So don’t be afraid of consuming dietary fat even though you want to burn fat.  There’s definitely an optimal amount.

In order to maintain your hormone health, your fat intake should not dip below 20% of your total caloric intake, or 1.1g per lb of bodyweight.

  • So for someone who weighs 200l
    bs and has set their calories to 2000 per day, that would be 45g of fat, minimum.

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How to Track your Macros For IIFYM


Tracking your macros on IIFYM

Tracking your macros on IIFYM

Once you know how many grams of each macronutrient you should consume every day, it’s critical to track your food intake to determine whether you meet your macros.

That way, if you eat a donut, you know how much protein, carbs, and fats it contained, and then the rest of your meals for the day can adjust accordingly.

NUTRITION LABELS

The first step to tracking your macros is to know where to find them.

They can be found on nutrition labels which will typically show the amount of fat on the top, followed by carbohydrates and protein, in grams.  These are the numbers you will track towards your total macro goals. Be sure to note the serving size and adjust the macros according to how much you eat.

USING AN APP

There are many apps available to download to help you keep track of the foods you eat as well as the macros.  When using an app, you can keep track of how close or far from your goals you are as you eat throughout the day.

Some of the most commonly used applications for tracking are:

  • MyFitnessPal

  • MyMacros+

  • Cronometer

  • Lose it!

What About Vitamins And Minerals?


Eating vitamins and minerals on an IIFYM diet for weight loss

Eating vitamins and minerals on an IIFYM diet for weight loss

One of the biggest appeals of IIFYM is the flexibility it offers, as essentially you can eat whatever you want, as long as it fits your macros.

When following IIFYM, it’s still important to be conscious of your vitamin and mineral intake and not over-doing it on junk food just because you can fit it into your macros.

For example, a diet consisting heavily of unhealthy items such as pizza, cookies, and candy would not provide adequate vitamins and minerals.

Although this could provide you with the means to meet your macros, it would not be a sustainable diet for a healthy, functioning body. Not only would you be facing a shortage of necessary vitamins and minerals to fight off diseases, feel energized, or build strong bones, you wouldn’t be able to lose weight as efficiently.

This would hinder weight loss for 3 reasons:

1. Without enough vitamins and minerals, your energy levels would be very low and you wouldn’t be able to burn as many calories

2. Junk food does not make us feel as full as whole foods and vegetables, so the chances of eating over your macros is increased

3. Without enough vitamins and minerals, our body will not be able to burn fat as efficiently

So when we refer to IIFYM, the goal is to hit your macros, and while there is certainly room to consume traditionally unhealthy food options (i.e. pizza and cookies), we still need to ensure that as a whole we’re finding foods that are rich in vitamins and minerals (i.e. whole foods and vegetables).

Other Tips For Weight Loss


Fitbod app

Fitbod app

Diet and exercise go hand-in-hand.

One of the key principles in any fat loss strategy is to use resistance training to build muscle and burn calories.

Even if you can only workout once per week, studies show that it can lead to meaningful results in strength gain, muscle gain, and weight loss.

For those looking to lose weight, I recommend the Fitbod app.

The Fitbod app provides you with tailored workouts that are based on your prior workout history, available equipment, level of expertise, and goals.

All you need to do is set your preference, and the workouts will self-populate every time you’re ready to exercise.

Sign up for 3 free workouts HERE.

Final Thoughts

IIFYM is a great dieting option for weight loss. It involves calculating how much protein, fat and carbohydrates you need to eat in a day to lose weight and then tracking your food intake to make sure you hit those numbers.

IIFYM works for weight loss because it not only controls your caloric intake but ensures the right amount of macronutrients are being consumed for your body type and activity level.

For weight loss, the general recommendation is to start in a 10% caloric deficit.

From there, set your macros depending on your activity level within the following ranges:

  • Protein: 1 – 1.25g per lb of bodyweight

  • Carbohydrates: 25-40% of calories

  • Fats: remaining calories, minimum of 1.1g per lb of bodyweight or 20% of calories

As well, IIFYM isn’t overly restrictive so people are able to stick with it long-term as they can still enjoy the foods they love.

About The Author


Maggie Morgan

Maggie Morgan

Maggie Morgan is a level 1 PN certified nutritionist who specializes in sport, exercise and performance nutrition, a strength training coach, and an elite level athlete. Maggie has competed in bodybuilding, and is an international-level powerlifter. Currently undertaking her Masters in Counselling Psychology, Maggie is not only able to lead others in strength and aesthetics through her personal experiences and scientific nutritional foundations but additionally by addressing the psychological and behavioral implications of exercise and nutrition. Through her writing and work with clients, Maggie works to provide information that’s responsible, rational and backed up by research, science, and fact within the health and fitness industry.