Sep 7, 2017
Meet in the Middle
Gillean Barkyoumb

An athlete comes to you with an outstretched arm holding a smartphone. On the screen, you see an Instagram feed of sculpted physiques lifting weights intermingled with pictures of pancakes dripping in syrup, loaded slices of pizza, and sticky-sweet donuts. Under each photo, you notice #IIFYM. “I want to try this,” your athlete says. But what exactly is “this,” and will it truly help them?

Getting a lot of play on social media, IIFYM stands for the If It Fits Your Macros diet, also known as flexible dieting. It’s a fueling trend that first gained popularity among CrossFit athletes and bodybuilders, and it’s slowly making its way into the athlete mainstream. Much of the buzz around it has been driven by Instagram, where more than eight million posts appear with #IIFYM, and one IIFYM and flexible dieting account alone has more than 120,000 followers.

In its most basic form, flexible dieting focuses on how much an individual eats as opposed to what they eat. But rather than focusing solely on total calorie intake as many traditional diets do, flexible dieting tracks consumed grams of the macronutrients — protein, carbohydrates, and fat.

Athletes following IIFYM create a diet that provides the right amount of protein, carbs, and fat (macros) for their personal needs based on their gender, height, weight, activity level, and fueling goals. Think of IIFYM as having a nutrition budget. As long as athletes reach their daily allotment of macros, they should be able to meet their respective body composition or performance ideals.

One of the most popular, yet controversial, features about following flexible dieting is the idea that athletes should be able to enjoy any food they want. It is based on the theory that a calorie is a calorie, no matter the source. So under this plan, a donut or brownie is more than okay, just as long as the athlete accounts for it in their total macro intake for the day.

Because of this, detractors of flexible dieting say it doesn’t place enough emphasis on food quality. There’s also a concern that IIFYM focuses too much on macros while neglecting other vital nutrients. However, proponents of the plan say when done right, IIFYM provides a solid balance of moderation and flexibility.


Unlike some of your athletes, you can see past the Instagram pictures celebrating IIFYM and want to know why you would encourage athletes to try it. As it turns out, flexible dieting can have numerous benefits for them. And while it is probably most popular in power sports, all athletes can see results with it.

Balanced macronutrient intake: Perhaps the biggest advantage of following IIFYM over other fueling plans is that it accounts for all three macronutrients. Many fad diets reduce or eliminate a macronutrient (think low fat, low carb, etc.), leaving the athlete feeling deprived and often leading to overindulgence. While these diets may work for the short-term, they are not realistic lifelong eating routines and can be especially harmful to athletes who push their bodies on a daily basis.

IIFYM is better than simply counting calories for the same reason. An athlete may think they are fueling optimally if they stay under a set number of calories per day, but it’s easy to miss out on one or more of the macronutrients in the quest to reach a daily calorie goal.

Athletes’ subpar food choices will show up in their daily intake, and they will have to adjust accordingly. For example, an athlete can enjoy a carb-heavy stack of pancakes at Saturday brunch, but then they must tweak their carb consumption for the rest of the day to make sure they don’t exceed their total macro budget.

Customized diet plan: Flexible dieting provides a way to create personalized nutrition regimens around individual training styles and performance goals. Athletes are more aware of what they are eating and how they can tweak their diet to maximize their output. So they have the option to increase carbohydrate intake if they feel fatigued at practice or boost carbs and protein if they’re sore the morning after a tournament.

IIFYM can also easily be altered throughout different training times of the year to keep athletes in their best shape. For instance, they may want to decrease the amount of carbohydrates consumed in the offseason because they are no longer having multi-hour long practices. Instead, they could raise protein consumption to better take advantage of weight training.

Other fad diets often don’t allow for this level of customization. Think of athletes following a low-carb or low-fat plan. They usually have to adjust their fueling to fit the parameters of the diet, rather than the diet working to accommodate their needs.

Flexibility: We all know that high school and college athletes aren’t going to eat at the dining hall or freshly prepare their own meals every day — there will be dinners at the local pizza place, movie nights with friends, or a Saturday brunch. IIFYM allows athletes to engage in these activities and eat the foods they enjoy in moderation without falling off their diet plan or experiencing guilt. This may keep athletes on track for the long term rather than throwing in the towel when cravings hit. Traditional models of fueling for performance don’t always offer this level of flexibility.

Accountability: That being said, IIFYM doesn’t give athletes leave to go totally off the rails with their diet. Rather, it holds them accountable for what they choose to eat. High school and college-aged athletes often have diets lacking in key nutrients due to poor access to quality foods, budget restrictions, and nutrition misconceptions. With IIFYM, their subpar food choices will show up in their daily intake, and they will have to adjust accordingly. For example, an athlete can enjoy a carb-heavy stack of pancakes at Saturday brunch, but then they must tweak their carb consumption for the rest of the day to make sure they don’t exceed their total macro budget.

In addition, by tracking their intake, athletes can start to see how diet affects performance. Before trying IIFYM, a soccer player may think they are getting enough carbs to fuel their games. However, when they actually record their macros with IIFYM, they may notice they are nowhere near what’s recommended for optimal performance.

Body composition goals: IIFYM has become a favorite for athletes looking to gain muscle or lose fat because it ensures proper macronutrient balance and allows for individualization. For instance, IIFYM can work for both a freshman football player wanting to put on weight and a seasoned cross-country runner seeking to cut body fat. While both will follow the principles of flexible dieting, their intakes will be extremely different. The football player will have a bigger budget of macronutrients with more carbohydrates and fats, and the cross-country runner will have a smaller budget and will need to be stricter with food choices. (See the case studies below for more on how to use IIFYM to meet body composition goals.)

Flexible dieting has become especially popular with athletes looking to lose fat because it doesn’t require them to deprive themselves to meet their goal. In this way, it can be a better option than simple calorie restriction, which can include strict calorie counts, approved food lists, and complete elimination of food groups. Further, workouts and overall energy levels can suffer on calorie restriction. Athletes who’ve had results losing fat on IIFYM say it allowed them to maintain high energy levels and continue to train hard.


For as many possible benefits as there are for IIFYM, it’s by no means a perfect plan. So if you have an athlete who is intent on giving flexible dieting a try, be sure they know the cons as well as the pros.

Food quality concerns: The greatest potential shortcoming of following a flexible dieting plan is that the basic framework places little emphasis on food quality. For example, a McDonald’s chicken sandwich contains 25 grams of protein, 33 grams of carbohydrates, and 15 grams of fat, while a meal of brown rice and tuna has the same macronutrient composition. Obviously, the brown rice and tuna is a healthier and better option for an athlete, but based solely on total macronutrient intake, either is technically acceptable. This can lead to an individual choosing poor quality macro sources.

The key to doing well on IIFYM for athletes is not taking meal flexibility to the extreme. It’s fine to enjoy something sweet, savory, or salty every now and then, but flexible dieting is not an excuse to eat junk food all the time. To achieve optimal body composition and performance, food quality must be considered.

Lacking other nutrients: It’s clear IIFYM places a heavy emphasis on getting enough macronutrients. However, it is important for athletes to ensure they are getting adequate amounts of micronutrients (vitamins and minerals) and fiber, as well. Unfortunately, flexible dieting does not provide guidance in that respect.

So, if an athlete wants to try IIFYM, make sure they pay attention to their micronutrient and fiber intake by encouraging them to focus on lean proteins, complex carbohydrates, healthy fats, and fresh fruits and vegetables. Athletes can also consider vitamins and mineral supplements to make up for any deficient micronutrients.

Tedious recording: Flexible dieting requires athletes to track their total grams of protein, carbs, and fat consumed every day. It is important to be very diligent and disciplined with this, which can take a lot of time, so it can be tough to fit in the busy life of a high school or college athlete.

There are some ways to make the recording process easier, though. For starters, there are numerous apps that can help, such as MyFitnessPal. One great thing about most of these apps is they recognize the user’s “favorites” or snacks/meals the individual eats often. So the more the athletes use the app to record intake, the more intuitive and faster tracking will become.

Another piece of advice is to encourage athletes to find a routine for when they record their macros. Maybe they enter their numbers for breakfast and lunch in the afternoon because they have some free time between classes, or perhaps they do it right before bed to cover their whole day in one shot. Finding a system that works for them will help streamline the process.

Potential for disordered eating: Because IIFYM necessitates a certain level of obsessiveness surrounding monitoring and tracking food, a fairly serious concern is the possibility that it can cover up or foster an unhealthy relationship with food. For this reason, athletes who have a history of disordered eating or may be prone to developing a disorder should not adopt the fueling plan.

Athletic trainers and strength coaches must be vigilant for this and pay attention. If an athlete is obsessing over their dietary intake or losing an excessive amount of weight with IIFYM, reach out to a registered dietitian for guidance.


If your athlete knows all the potential pros and cons of IIFYM and still wants to pursue it, get them started the right way. First, make sure they have a general knowledge of nutritious foods so they can do IIFYM appropriately. One way to make sure athletes have a good nutritional foundation is to invite a registered dietitian to speak with them about proper fueling on the IIFYM diet.

Next, consider when would be the ideal time for the athlete to dive into this new eating plan. The offseason is probably the best choice because it gives the athlete a chance to “test the waters.” There is usually some degree of tweaking needed when starting flexible dieting, and you don’t want that to hinder performance during the season.

After settling on a time to begin IIFYM, the athlete must calculate how many macros to consume each day. Start by having them determine their total daily energy expenditure (TDEE) or how many calories their body burns each day. There are online calculators to get this number, and it’s based on a variety of factors, including height, weight, and activity level. If the athlete wants to maintain their current body composition, they would aim to consume their TDEE amount of calories daily. To gain muscle, they would shoot for more than their TDEE, and to lose fat, they would reduce their calorie intake.

Then, the athlete should calculate how to distribute those daily allotted calories among the macronutrients using the U.S. Department of Agriculture’s Acceptable Macronutrient Distribution Ranges: 45 to 65 percent from carbohydrates, 10 to 35 percent from protein, and 20 to 35 percent from fat. There are many websites that will compute this for athletes, such as To transfer from calories to grams for each macro, use these conversions:

• One gram of protein = four calories

• One gram of carbs = four calories

• One gram of fat = nine calories.

Going off the recommended ranges, athletes can customize their macro intake based on their body composition goals, sport, and duration and intensity of training. Other factors such as age, gender, and current weight should also be considered. It’s difficult to give suggestions since the appropriate macro amount is so specific for each individual, but here are a few recommendations to provide guidance:

• Endurance athletes need to be on the higher end of the carbohydrate range.

• Athletes looking to lose weight and get lean should consider a higher amount of protein.

• Athletes who feel hungry constantly or unsatisfied after meals can try increasing fat intake.

As athletes get going with IIFYM, most will need to further adjust their macro intake to some extent, especially if they start to feel depleted or have trouble recovering after workouts. If they are feeling fatigued, they likely need to consume more carbohydrates before and during activity. (Hydration may be a factor, as well.) To improve recovery, athletes should grab a post-workout snack that balances carbohydrates to refuel glycogen stores and quality protein to rebuild and repair muscle fibers.

In addition, athletes should pay attention to nutrient timing within IIFYM. Consuming the right amount and kinds of carbohydrates and protein before and after workouts can keep them fueled, assist in muscle growth and recovery, and prevent injury. Tell them to get complex carbohydrates throughout the day and during exercise and budget around 30 grams of protein after activity for optimal fueling.

Another important factor to consider often gets forgotten once athletes get wrapped up in counting their macros: hydration. Staying hydrated should be a top priority for athletes following flexible dieting. A general rule of thumb is to have the athlete drink half their weight in ounces per day.

Once the athlete has set and refined their daily macronutrient totals, it helps for them to create a plan and stick to it. Long-term compliance is essential for maintaining results with flexible dieting. One common strategy is to have athletes write out a plan for the week and schedule times for meals and snacks, so they are less likely to skip eating or resort to unhealthy temptations.

Overall, flexible dieting can help athletes become more aware of the nutrient composition of foods, which can result in long-term, healthy habits. Rather than labeling foods as “bad” or “good,” it allows all foods in moderation. While tracking intake can be tedious, and it’s important to harp on food quality, when done correctly, IIFYM can help athletes gain a winning edge.



Andy is a 185-pound baseball player trying to lose 15 pounds of body fat on the If It Fits Your Macros (IIFYM) diet during the offseason. His total daily energy expenditure (TDEE) is 2,733 calories.

To lose fat, Andy will need to reduce his calorie intake. Decreasing total calories by about 500 a day is a good starting point for targeting fat loss because it supports a healthy weight loss of one to two pounds per week. For Andy, this means reducing his daily intake to 2,233 calories.

Now it’s time to convert calories into appropriate macronutrient amounts for Andy. Because he wants to lose body fat and lean up, he starts with the higher end of the recommended protein range (35 percent of total calories), in the middle of the fat range (20 percent), and lower on the carbohydrate range (45 percent). Using these figures, his daily macro values are:

• Protein: 781 calories or 195 grams

• Fat: 446 calories or 50 grams

• Carbohydrates: 893 calories or 223 grams.

After two months of following the IIFYM program and tracking his intake, Andy loses 10 pounds of fat and starts to notice more muscle definition in his arms and legs. Flexible dieting allows Andy to pursue his goal while still enjoying some of his favorite indulgent foods on the weekends.

As the season approaches and two-a-day workouts begin, Andy works with his team dietitian to tweak his intake to include more carbohydrates for fuel (50 percent of total calories) and decrease protein (30 percent). While he is still working toward losing five more pounds, he wants to properly fuel his body for optimal performance during the season.

Sidebar 2:


Sara is a 130-pound softball player trying to put on five pounds of muscle mass with the If It Fits Your Macros (IIFYM) diet. Her total daily energy expenditure (TDEE) is 2,331 calories.

To add muscle, a good starting point is to increase calories by 250 to 500 per day, with a goal of gaining half a pound to one pound of muscle per week. The key is to add weight gradually to avoid fat, rather than muscle, gain. Sara starts by increasing intake by 250 calories, so her total daily consumption is 2,581 calories.

Then, we convert calories into appropriate macronutrient amounts for Sara. Because she wants to increase muscle, she starts on the higher ends of the recommended protein range (30 percent of total calories) and carbohydrate range (50 percent), so she can have the energy needed to build muscle and fuel her workouts. Her fat intake will be in the lower range (20 percent). Her daily macro totals are:

• Protein: 774 calories or 194 grams

• Fat: 516 calories or 57 grams

• Carbohydrates: 1,290 calories or 322 grams.

To maximize muscle gain, Sara pairs her diet plan with an intense weight lifting regimen. She has great success for the first month but then injures her ankle and has to take two weeks off. While sidelined and fairly sedentary, she maintains the macronutrient ranges but decreases her total calorie intake to about 2,000 per day.

Now that she is cleared to get back into the gym, Sara will increase her intake in 250-calorie increments to avoid fat gain. Her goal is to get back to the initial plan of 2,581 calories once she can train at full intensity.

Image by Tech. Sgt. Christina M. Styer

Gillean Barkyoumb, MS, RD, is a nutritionist based out of Gilbert, Ariz., and the creator of, a site dedicated to exploring the shift in today's food culture. She can be reached at: [email protected].

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