IIFYM: A Runner's Guide to Macros

If you haven’t heard of IIFYM, it’s an acronym for “fabulous diet plan you haven’t heard of till now”.

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Just kidding. In case you have been spending too much time in your man-cave/she-sled, IIFYM means ‘if it fits your macros’. ‘Macros’ is an abbreviation for macronutrients. And macronutrients are basically nutrients required in relatively larger amounts within your diet, of which the key ones include carbohydrates, proteins and fats. To understand the concept of IIFYM, it might help to know that it is also called flexible dieting.

So What’s IIFYM Really About?

IIFYM is actually a diet regime that focuses on meeting the daily intake levels of the various macronutrients, as opposed to an emphasis on the exact types of food to eat. Thus, for instance, instead of banishing certain food types while religiously consuming others, you would be ensuring that you meet your daily intake of carbohydrates, protein and fat. Being less restrictive, an IIFYM diet can potentially mean less mental and emotional strain. After all, diets that are too strict may result in an emotional burnout that compromises your interest in healthy eating, or even healthy exercises i.e. running.

How Is IIFYM Better Than Counting Calories?

Chances are, you might be a runner to lose fat or limit weight gain. With temptations like Chilli Crab, Fried Prawn Noodles, and Laksa, who can blame a Singaporean?

The advantage that IIFYM has over simple calorie counting lies on this premise: that maintaining a calorie deficit may not be enough, say if you want to lose weight while maintaining your lean mass. It ensures that you can lose weight without the lost kilos coming from the muscles you are losing, which can potentially happen if you use the simple calorie deficit method.

Here’s why. As a runner, you would likely want to preserve your muscles and maintain training intensity. To accomplish these, you would have to ensure that you’re eating enough protein and carbohydrates (to provide muscles with glycogen stores) respectively. Also, healthy fats play a crucial role in the production of your bodily hormones.

Thus, to achieve your IIFYM diet targets, you can opt to get your protein from a juicy beefsteak and not boiled chicken breast; your carbs from a deli sandwich and not just potatoes; and your fats from mozzarella cheese sticks and not just avocados.

What Are My Macro Needs?

You can simply use an online calculator to calculate how much of the various macronutrients you need.

Your needs will differ based on your body, lifestyle and training intensity. Take sports writer Amanda Brooks for instance. When not in full marathon training mode, her needs in percentages are 40% carbohydrates, 30% protein and 30% fat. During marathon training, her percentages are 60% carbohydrates, 25% protein and 15% fat. Notice that during the non-intensive training period, there’s an increased protein level, which helps muscles repair and recover.

Does This Mean I Can Eat Junk Food Every Day?

Probably not, unless you secretly wish to test the limits of your health insurance. Just because you can go on a Twinkies diet and still lose weight, does not necessarily mean you should.

Don’t forget that food is your source of essential micronutrients like vitamins and minerals, which your body needs to perform well, and which you probably cannot get from just Pringles, Ben and Jerry’s, sweet desserts, fast food and processed food.

“Thus, for instance, instead of banishing certain food types while religiously consuming others, you would be ensuring that you meet your daily intake of carbohydrates, protein and fat.”


So whenever you’re feeling inspired to attain a better, healthier body, it’s no longer just marathon sign-up pages or running drills you can browse. Looking at meal ideas can also serve similar purposes - unless you’re drooling over #foodporn instead of IIFYM meal plans.


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LIV3LY Editor
LIV3LY Editor

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