How Flexible Dieting IIFYM Can Help You Cut Fat and Build Muscle

There’s a new trend gaining popularity among those wanting to cut fat and gain lean muscle and it’s called flexible dieting or IIFYM (If It Fits Your Macros).

Basically, it teaches you how to count macros in a way that will accomplish your goals. The best thing about flexible dieting is a person’s ability to eat whatever they want as long as it fits their prescribed set of macro amounts for the day.

  • Carbs are fine.
  • Fat is fine.
  • Sugar is allowed.
  • Even fast food can be eaten (within reason and limited).

Here’s how the whole thing works.

Flexible Dieting / IIFYM Guidelines

We all have heard the saying that if you want to lose weight, you have to eat fewer calories than your body requires and if you want to gain weight, you have to eat more calories than your body requires.

All diets use this philosophy as their basis but many go about it in somewhat of a haphazard way.

  1. Some prescribe a set daily calorie goal.
  2. Others say to simply cut out carbs.
  3. And others say to eliminate fat from your diet.

While all these methods can help you reduce calories, they neglect to account for individual differences and establish how much energy the individual actually needs during a 24 hour period.

However, flexible dieting starts by using a much more scientific approach. (Here’s a great resource for understanding the philosophy behind flexible dieting: Before any eating plan is established the person’s TDEE (total daily energy expenditure) is established.  This is simply the combination of one’s REE (resting energy expenditure or BMR) and a person’s movement. A person’s movement can range from sedentary (normal daily activities) to extremely active and everywhere in between. You then calculate what kind of calorie deficit you need to be in order to accomplish your

You then calculate what kind of calorie deficit or surplus you need to be in order to accomplish your fat loss or muscle building goals. This ranges from -20% to +20% of your maintenance TDEE.

[ has an easy to use TDEE and IIFYM macro calculator that can get you started. ]

Once the TDEE is determined, macronutrients (macros) are then calculated in a way that helps a person best reach his/her desired goal.

There are three main macronutrients in all the foods you eat and they supply varying amounts of energy.

  • Protein: 4 calories per gram
  • Carbohydrates: 4 calories per gram
  • Fats: 9 calories per gram.

Alcohol also supplies calories at 7 per gram.

Once you have your TDEE and macros calculated, you then begin tracking what you eat.

Counting Macros in the Food You Eat

If there’s a downside to flexible dieting, it’s the necessity of tracking all the food you eat. Since this is a very scientific approach, keeping track of the exact macros you are eating throughout the day is crucial.

This can be a time-consuming process, but it gets easier with practice and there are several good smartphone apps that can help.




Are good options and soon the whole process is pretty fast once your common foods and meals are in your food log. You just eat foods as your normally would and keep eating until you hit each of your macro goals.

Sometimes you may have hit your fat and protein goal but still have carbs left. When this happens you eat a food that is almost purely carbs like fruit.

Does IIFYM Mean I Can Eat Junk Food?

You can technically work in anything as long as it fits your macros, but your goal should also be better health.

The majority of your macros should be met with nutritious whole foods, but allow yourself some treats each day. Completely cutting out treats and food you love usually leads to feelings of deprivation and eventually binge eating. By satisfying your cravings for foods like french fries and potato chips from time to time it can prevent you from overeating these foods after a long period of restricting them from your diet.

Does Flexible Dieting Work?

This is the most important thing, right? Flexible dieting is just as effective as any diet plan but is a lot more sustainable long-term because there aren’t food restrictions, extremely low-calorie requirements, or the need for special/expensive supplements.

I encourage you to search around on Instagram with the hashtag #iifym or #flexibledieting and you’ll see a lot of people posting pictures of their personal results.

If you want to eat what you want and still accomplish your fat loss and muscle building goals then learn more about flexible dieting over at Healthyeater and get started today.

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