What Is IIFYM?
For the longest time, when it came to weight, the number of calories you consumed was the only thing that mattered. If you wanted to control your weight, you needed to control your calories. Have a caloric deficit, and you would lose weight. Consume excess calories, and you would stack on the weight.
While this approach worked for some, it proved limiting and ultimately unsuccessful for others. One reaction to this type of dietary approach was the development of IIFYM, also known as flexible dieting.
IIFYM stands for If It Fits Your Macros. Competitive bodybuilders tired of eating bland and boring food when dieting for bodybuilding contests believed calories were only the beginning of the story and developed the idea for IIFYM.
Followers of this diet focus on eating a certain amount of macronutrients, respecting each one’s unique role, rather than only counting calories.
Because all foods are allowed, and nothing is off-limits, many consider IIFYM a welcome change from strict calorie counting or the elimination of entire food groups. IIFYM, typically used for people who want to lose weight, can also be modified for those who want to put on muscle or gain weight.
What Are Macros?
Macros is short for macronutrients; the term used to describe the three major nutrients: protein, carbohydrates, and fat tracked on an IIFYM diet. Some combination of these three macronutrients makes up everything you eat and drink (except for water and alcohol). Alcohol, not included in the IIFYM diet, is the fourth macronutrient.
Rather than placing all the emphasis on calorie counting or restricting certain food groups, IIFYM focuses on meeting daily targets of each macronutrient. A typical IIFYM breakdown consists of 25-30 per cent of calories from protein, 25-30 per cent of calories from fats and the remainder from carbohydrates.
Your specific target macronutrient breakdown will vary depending on personal factors such as weight, height, gender, activity level, and specific goals. Someone looking to gain muscle will eat differently than someone trying to lose weight. Likewise, macronutrient ratios will look different for someone who is training for a marathon compared to someone doing weightlifting five times a week.
The basic idea of IIFYM is simple; however, making it work requires a good understanding of key nutritional principles. You can definitely do IIFYM wrong, but with the right approach, it can help you achieve your goals and create healthy, long-term eating habits.
It is important to remember that your food choices aren’t just about hitting numbers. The foods you eat impact your blood sugar, energy levels, cholesterol levels, and overall health.
How to Calculate Your Macros
When starting the IIFYM diet, the first step is calculating your macros.
The original IIFYM website has a free macro calculator and popular apps like My Fitness Pal also have macro calculators. You can also calculate your macros manually using standardised equations. Unless you’re a maths whiz, it is easier to use an app or a website.
The general process for calculating your macros is:
Calculating your basal metabolic rate (BMR): This is the amount of energy your body needs at rest and goes toward essential functions, such as breathing, circulation, and body temperature. Equations will determine how much energy your body uses at rest based on age, sex, height and weight.
Adjusting for activity level: The next step involves factoring in the average physical activity level, which affects the number of calories the body uses each day. This measurement is called total daily energy expenditure (TDEE).
Adjusting based on weight goals: For weight loss, calorie intake is reduced by 15–25%. For weight gain calorie intake is increased by 5–15%.
Determining your macros: Protein intake will be between 1.5 and 2.2 grams per kilo of body weight. Fat intake will be between 0.5 and 0.9 grams per kilo of body weight. All remaining calories are allotted for carbs. Your goals will determine your specific macro allocation.
After completing the calculations, the final IIFYM plan will tell you the total calories and amounts of protein, fat and carbohydrates you should consume each day. How you meet that calorie intake and the targets for individual macronutrients is up to you.
How To Meet Your Macros
Once you know the amount of each macronutrient you should be consuming the next step is to track your food intake. Weighing your food is also recommended to get the most accurate macronutrient calculations.
With the growing popularity of this dietary approach, there are many apps today that help you track your calories and macros Some popular tracking apps like My Fitness Pal, My Macros+, Lose It!, and Chronometer can help track your macro intake. Some of these apps have significant nutrient and food databases, making it easy to find and track most foods and allowing you to track your intake on the go. Some may also include barcode scanners simplifying the process of monitoring your food intake.
Despite having no restrictions on the food you can include, it is much easier to meet your macros with whole foods like fruits, vegetables, high-quality proteins, nuts, seeds and whole grains. It also helps to understand which foods contain the highest amounts of each macronutrient so that you can allocate them appropriately.
Carbohydrates contain four calories per gram and are the body’s preferred primary energy source. There are two types of carbohydrates, simple and complex.
Complex carbohydrates take longer to digest and provide a more steady source of energy than simple carbohydrates. Complex carbohydrates are often darker in colour and contain an abundance of vitamins and minerals. Examples include oats, brown rice, starchy vegetables, and wholemeal bread.
Simple carbohydrates are made up of shorter molecule chains, meaning they are digested more quickly and lead to spikes in blood glucose. Some whole foods such as milk and fruit contain simple carbohydrates, but they are also found in processed foods such as sugars and syrups, candy, soft drinks and some baked goods and cereals.
As a general rule, the more complex the carbohydrate, the better it is for you. Complex carbohydrates are more nutrient-dense, higher in fibre and more filling. Fibre content is an important thing to consider as part of your carbohydrate intake.
Foods High in Carbohydrates
- Bread, cereals, pasta and baked goods
- Legumes: beans, lentils, peanuts, peas and soy
- Grains: oats, wheat, barley, rye and rice
- Fruits, especially banana, mango, apple and pineapple
- Starchy vegetables like potatoes, sweet potatoes, pumpkin and corn
Protein contains four calories per gram and is an essential nutrient made up of a combination of amino acids. These amino acids are the building blocks of body tissue and used to grow and maintain cells. Protein promotes feelings of fullness and is beneficial for exercising individuals looking to lose weight or gain muscle.
Foods High in Protein
- Meat: beef, chicken, lamb, pork and turkey
- Dairy products: cheese, milk, whey protein and yogurt
- Seafood: fish and shellfish
- Legumes: beans, lentils, peanuts, peas and soy
Fat contains nine calories per gram and is an essential nutrient involved in many bodily functions. Making up over 50% of cell membranes, It’s crucial for cell signalling and communication in the body. Fat also allows your body to absorb specific vitamins and promotes an optimal hormonal balance.
Fats are further subdivided into three different types:
Unsaturated fats: Unsaturated fats are liquid at room temperature. They are typically regarded as beneficial or healthy fats because they positively impact heart health, cholesterol levels and cognitive function. They can also reduce inflammation.
Unsaturated fats are mostly found in plant foods such as vegetable oils, nuts, and seeds. They can also be obtained from foods such as fatty fish and avocadoes.
Saturated fats: Saturated fats are solid at room temperature. Decades of dietary advice suggested this type of fat was harmful; however, this idea has evolved in recent years. Current research supports the fact that nutritious wholefoods high in fat can be included as part of a healthy, well-rounded diet. Today, experts advise that cutting back on saturated fat can be good for health if people replace it with good fats, especially, polyunsaturated fats.
Saturated fats are found in animal products such as meat, milk and cheese, and plant-based oils such as coconut and palm oil. Some processed foods like fried food and many fast foods are also high in saturated fat.
Trans fats: These are referred to as “bad” fats because they negatively impact heart health and cholesterol levels and contribute to inflammation and insulin resistance.
These are often found in baked goods, processed snack foods, and margarine but are also found in beef and dairy fat in small amounts.
Foods High in Fat
- Egg yolks
- Fatty fish: salmon, sardines and anchovies
- Full-fat dairy products: cheese, cream, whole milk and yogurt
- Nuts and nut butters
- Oils from fruits, nuts and seeds
- Seeds, like chia and flax
Alcohol is the fourth macronutrient, containing 7 calories per gram, but it’s not included in the IIFYM diet.
Making The Right Choices
Just because IIFYM technically allows you to eat whatever you like, it shouldn’t be considered a license to eat like a child. Done right, IIFYM can support a balanced diet that also leaves room for your favourite treats in moderation. It can be an effective, sustainable way to lose weight. But, it’s still important to follow basic healthy eating guidelines. You can certainly do IIFYM wrong.
It is always a good idea to choose whole foods over processed foods, emphasising vegetables, fibre, and high-quality protein.
Carbohydrates come in many forms, from lollies, chips and cookies to vegetables, fruit, and whole grains. You can still work your favourite treats into the IIFYM plan. But it is important to remember that they are treats, not staples.
Simple, refined carbohydrates will give you a short energy spike followed by a subsequent crash. Fibre-rich options such as fruit, oats and brown rice will provide a more sustained release of energy. The source of carbohydrates you choose will significantly affect your energy levels, performance and recovery.
Pizza, doughnuts, and ice cream may taste great, but if they are your only fat source, you have a problem. These foods are high in fat but devoid of the healthy fats that improve heart health, cholesterol levels, and help promote a leaner body composition.
Keep your treats as treats. You should aim to fill your fat quota with healthy fat sources like fatty fish, nuts, seeds, egg yolks, oils, and avocadoes. These will provide your body with a wide variety of heart-healthy, recovery-supporting fats.
It’s beneficial to know the difference between complete and incomplete proteins. Many plant-based proteins are considered incomplete because they lack one or more of the essential amino acids. Low-quality proteins shouldn’t be counted towards your total protein total. Peanut butter may have 8 grams of protein per serving, but it is better to count it as fat because it’s an incomplete protein.
High-quality, complete protein sources are meat, seafood, eggs, quinoa and soy. These proteins are nutrient-dense, support muscle growth and recovery, and help keep you full without excess calories. If you follow a plant-based diet, you can also pair complementary proteins such as beans and rice to ensure you get all the essential amino acids.
Benefits of IIFYM
Following the IIFYM diet has several benefits:
It Can be Educational
Because IIFYM focuses on macronutrients, rather than calories, it can be a great educational tool for people unfamiliar with the macronutrient composition of foods.
A Mars bar and 120g of salmon have a similar caloric content but have a very different macronutrient profile. They both contain large amounts of fat. However, the Mars bar is high in carbohydrates, while the salmon has a high protein content.
For someone who has never looked at the macronutrient composition of foods, tracking their macros can be an eye-opening experience.
It Emphasises the Importance of All Three Macronutrients
One benefit of IIFYM is that it emphasises the idea that all three macronutrients; fat, carbs, and protein, are important. This emphasis keeps people from eliminating or restricting a single group.
Many dietary guidelines highlight the importance of a balanced diet for overall health. Unlike other low-carb or low-fat dietary approaches, an IIFYM approach can help people stop fearing certain food groups and have a more varied diet.
It is Flexible
There are no forbidden foods on IIFYM. The diet promotes moderation and encourages people to eat a diverse range of foods as long as they do not exceed their macro targets.
This flexible approach can make it a more enjoyable experience and removes some of the pressure and guilt associated with more restrictive dieting methods. It can also teach balance and help people understand where they are getting most of their protein, fats and carbohydrates.
Rather than worrying about undoing all your hard work if you have a treat, you can still indulge while working towards your goals.
It Can Help You Achieve Your Weight Goals
At current, there is conflicting research on whether or not manipulating your macros affects weight loss. However, some evidence suggests that higher-protein diets, like IIFYM, can increase metabolism and help maintain weight loss longer.
Research consistently shows that calorie reduction leads to weight loss in the short term. Since the IIFYM diet reduces calories by 15–25% for people who want to lose weight, following the diet should result in weight loss.
Research also shows that increased calorie consumption leads to weight gain, and a higher protein intake can assist with muscle building. For those wishing to gain weight or build muscle, increasing calories and consuming more protein should help achieve those goals.
Disadvantages of IIFYM
No Focus on Micronutrients
Although no foods are off-limits on this eating plan, the foods you choose make a difference to your overall health. Vitamins and minerals, also known as micronutrients, are crucial for overall health and development. The body does not produce these essential micronutrients, and a person must obtain them from their diet.
With so much focus on macros, people following this diet may overlook the importance of micronutrients. There is no tracking to ensure people are getting enough of these vital nutrients.
A person following the IIFYM diet could choose to get their carbohydrates from donuts and chips rather than healthier sources like fruits and whole grains, and still eat within the diet’s confines. Likewise, suppose the majority of fat intake comes from saturated fats. In that case, you may be following IIFYM rules but going against common dietary recommendations of limiting saturated fat intake and replacing it with unsaturated fats.
For optimal health, it is crucial to incorporate a variety of nutrient-dense whole foods. They should be the norm, not the exception. IIFYM is not an excuse to skip vegetables in favour of cookies.
Can be Time Consuming
The act of weighing and tracking all your food may be complicated or time consuming for some people. IIFYM won’t work for you if you’re not careful about measuring your portion sizes. It’s easy to find many macro-friendly recipes online. However, they still require varying degrees of measuring and weighing your food.
Could Increase the Risk of Eating Disorders
Even if you have no history of eating disorders, tracking your food intake can potentially lead to unhealthy food behaviours. Some research finds a strong association between food and fitness tracking and eating disorder development, especially in young women.
While IIFYM allows people to indulge and is relatively flexible compared to more restrictive diets, there’s still a lot of food-based analysis or calculation involved. If tracking macros leads you to spend an unhealthy amount of time thinking about food, or it always makes you stressed about hitting your targets, you should stop.
It’s Still a Diet
While IIFYM is more flexible than many other diets, remember that it is still a diet.
Research often finds that dieting does not work over the long term, and many people end up regaining at least some of the weight they lost. Therefore it may be necessary to address other factors beyond diet such as motivation, sleep, stress, and underlying health or hormonal conditions.
Does Not Take Health Conditions Into Account
IIFYM is purely a means to improve body composition. IIFYM does not address health concerns of the heart, brain or other organs and places no emphasis on overall health.
IIFYM may not be appropriate for everyone, especially those with underlying health conditions that require special diets. People with diabetes need to monitor their carbohydrate intake, and those with kidney disease must watch their sodium, and protein consumption.
While it is possible to modify IIFYM to work for these conditions, it may require guidance from a dietitian or other health professional.
Frequently Asked Questions
Why Can’t I Just Count Calories?
Calorie counting, especially when prioritising healthy food sources and a balanced diet can work. If you’re in an appropriate caloric deficit or surplus, your weight will change. However, counting macros emphasises individual macronutrients, making it easier to customise for individual goals and training styles.
Training for a marathon? You will likely need more carbohydrates than the average person. Are you a competitive powerlifter? A higher protein intake is more suitable in this case. Having a set target and tracking the individual macronutrients will help you reach your personal goals.
Do I Need To Be 100% Accurate?
While tracking is a crucial component of this diet, there is no need to stress about hitting your macros precisely every single day.
You should still see results As long as you get within 10 grams of your protein and carbohydrate target and 5 grams of your fat target. If your target for carbohydrates is 250 grams, anywhere within 240-260 grams is OK. If your fat target is 60 grams, anywhere between 55-65 grams will also be acceptable. Don’t let perfection be the enemy of good.
Should My Macros Be The Same Each Day?
It is often recommended to keep macros the same regardless of training to make food preparation as simple as possible. However, your caloric needs are going to be different on rest days compared to hard training days.
You don’t need a separate macro split for every day of the week. But, it can be beneficial to differentiate between training days and rest days. When you don’t train, your need for carbohydrates will not be as great because you’re burning fewer calories.
Reducing your carbohydrates will help align your nutrition and training, particularly when weight loss is the goal. One recommendation is to cut back carbs by 30-50 grams on non-training days while keeping protein and fats consistent.
Once I Meet My Macros, Should I “Fill In” My Remaining Calories?
Say your daily calorie goal is 2000 calories, and you hit your macro target with 100 calories remaining. Don’t worry about making up those additional calories. Focus on the macros, and the calories will even out over time.
Your food choices will impact the total calories consumed, which will likely vary from day to day. Any caloric difference will usually work itself out over time when including a wide variety of nutritious whole foods.
The same applies if you notice you’re slightly above your calorie goal target. When meeting your macro targets with good food choices, a slight excess today will likely be evened out by a small deficit tomorrow.
Can I Still Have A Cheat Meal?
One of the major advantages of an IIFYM approach is that you can eat a combination of nutrient-dense foods along with your favourite treats. So technically, you can indulge daily in a bit of chocolate or a cookie as long as you meet your macros.
However, sometimes, it can be a nice psychological break not to track macros at all for a meal. For optimal progress, it’s best to limit these cheat meals.
Remember, you can still eat anything you want daily, as long as you watch your portions.
Can I Drink Alcohol?
Anyone looking at optimising their overall health should limit their alcohol consumption. However, social experiences are a crucial part of one’s happiness, and alcohol often forms part of these social experiences. You can still follow an IIFYM diet while including some alcohol in moderation.
As mentioned before, alcohol is the fourth macronutrient, and it contains seven calories per gram. Including it in your macros requires a little mathematics.
In general, the most flexible macro, especially from a fat loss perspective is carbohydrates. Fat and protein are both essential to our diet, whereas carbohydrates are not required to survive. Because of this, it is generally recommended to manipulate carbohydrate intake when replacing with alcohol. You can also manage fat intake, and sometimes a combination of both works well.
Let’s look at how that works. Say you have an alcoholic drink that contains 80 calories. We know that carbohydrates equal four calories per gram. We would divide 80 by 4 to give us a total of 20. This means that we could reduce our carbohydrate intake by 20 grams to create the right calorie balance. If we wanted to use our fat intake instead, we would divide 80 by 9 calories, giving us just under 9 grams. Reducing our fat intake by 9 grams would also give us the same calorie balance.
This process can work well on occasions where you might have a couple of drinks but should not be a regular occurrence.
While IIFYM means that technically you can eat ice cream, burgers, or pizza, and still lose weight. It shouldn’t justify or advocate eating mostly junk food to do so. Body composition and health are not the same things. Just because someone looks healthy, doesn’t necessarily mean they are. Health is more than a six-pack and a nice pair of biceps.
This dietary approach is supposed to be flexible and enjoyable. If you’re honest with yourself and track your intake correctly, you’ll set yourself up for success.
It is meant to liberalise food choice, not make you neurotic about choosing the most macro-friendly option at every meal. Trying to juggle macros to justify a big treat at the end of the day sets you up for failure and poor eating habits. You need self-control.
Aim to select nutrient-rich whole foods first. Once you meet your micronutrient and fibre needs, you can choose the foods you enjoy while staying within your macro targets. While IIFYM promotes diversity in one’s diet, your food choices will significantly impact your overall health and well-being.
AN IMPORTANT CAVEAT: I am not a medical practitioner or a dietitian. The information in this blog should be viewed as educational only.