What is Flexible Dieting?

by Dean McKillop 3712 views Nutrition

What is Flexible Dieting?

Now before you read through this article, which has been written to provide contextual fact, it's important we remove any previous bias you may have on flexible dieting and look at the content within. Then you can judge it on the content at hand as opposed to having pre-conceived ideas based on what you may have heard from a friend or seen on social media. 

What is flexible dieting?

Flexible Dieting is the term given to the former dieting concept known as IIFYM (if it fits your macros) and recognises that regardless of the food type consumed, provided that the law of thermodynamics is adhered to (calories in verse calories out) it essentially does not matter what food type you eat so long as it fits your macronutrient targets.

In essence, flexible dieting places no preferences on food type, but instead on food quantity.

NOW before I go any further, this definition can obviously be taken quite liberally and abused, but it is my opinion that this is not what was intended for IIFYM. Yes, there are individuals who choose to eat a diet based predominantly of processed nutrient devoid foods and claim "iifym" however, an outlier does not define what the majority do.

Just like religion or any belief system, there may be outliers, however defining the entire group based on the actions of a minority is unfair and unjust.

Coined many years ago on a bodybuilding forum, IIFYM originated after a forum member asked the board if he could merely swap a fruit or a vegetable for another source during his prep for a bodybuilding show, of which one coach answered, “if it fits your macros.”

Taken in the context of this conversation, IIFYM was simple, effect and reasonable acronym given to someone looking to swap a single food type in an entire diet for another.

Years on and we now have ‘fitness enthusiasts’ promoting diets laden with processed foods, minimal vegetable and fruit intake, hitting their macros and hashtagging #iifym as if it is a good enough excuse to simply eat whatever you want without nutritional consideration, all for a physique goal.

This is NOT what flexible dieting is about.

Flexible Dieting is simply having a nutritional understanding that in the context of an entire diet there are no good or bad foods, food types should not be negatively labelled and that you have the ability to eat both nutritiously in the physical sense but also consume foods that provide us with social and psychological freedom despite those foods not necessarily being nutrient dense.

You have to eat to grow!

Flexible dieting understands that in the context of a diet consisting primarily of animal products such as meat, dairy and fish for protein, grains, legumes and fruit for carbohydrates, nuts, avocados and oils for fats, that eating a small portion of non-nutrient dense foods like a lolly, a donut, some cake or even using things like sauce on meals is not going to affect body composition or physiological health.


Instead, flexible dieting recognises the benefits of all facets of dieting and instead of labelling foods as good or bad, a flexible dieter will consume a diet primarily of nutrient dense proteins, fats and carbs for physical health but will also include all types of food from various sources. In doing so a flexible dieter is not socially excluded due to food choice restriction but instead they have complete psychological control over the consumption of whatever food type they choose.

For example, let's look at the diet of this flexible dieter:

Foods Calories Carbs Fat Protein Cholest Sodium Sugars Fiber
Meal 1
Liddells - Lactose Free Skim Milk (100ml), 30 mls 11 1g 0g 1g 0mg 11mg 1g 0g
SNI - 100% Whey, 30 g 119 3g 1g 24g 0mg 0mg 2g 0g
Oats - Quick - Uncle Tobys, 70 g 268 40g 6g 9g 0mg 9mg 1g 7g
Aldi - Sweethaven - Frozen Mixed Berries, 100 g 47 9g 0g 1g 0mg 15mg 7g 4g
Nuttab - Mushroom Raw, 105 g 26 1g 0g 3g 0mg 0mg 0g 2g
Dairy Farmers - Low Fat Cottage Cheese, 50 g 46 2g 1g 6g 0mg 96mg 2g 0g
Pb2 - Chocolate, 6 grams 22 3g 0g 2g 0mg 35mg 1g 0g
Chobani - Greek Yogurt - Plain Fat Free, 200 g 120 8g 0g 20g 0mg 95mg 8g 0g
Riverina Fresh - Lite Milk - Low Fat, 120 ml 53 6g 1g 5g 0mg 47mg 6g 0g
Meal 2
Highland Park - Extra Lean Beef Mince, 307 g 385 2g 12g 68g 0mg 0mg 2g 0g
Steggles - Turkey Mince, 509 g 590 4g 20g 98g 0mg 338mg 4g 0g
Pastificio venturino - Wholemeal Artisan Penne, 100 g 337 67g 2g 13g 0mg 0mg 0g 2g
Nuttab - Butternut Pumpkin Raw, 400 g 188 29g 2g 9g 0mg 0mg 0g 7g
Old El Paso - Enchilada Sauce With Tomato & Capsicum, 50 g 19 4g 0g 1g 0mg 323mg 3g 1g
Fountain - BBQ Sauce no added sugar, 30 ml 14 3g 0g 0g 0mg 0mg 0g 0g
French's - Yellow Mustard, 20 g 14 1g 1g 1g 0mg 0mg 0g 0g
Fountain - Smart Tomato Sauce, 10 ml 5 1g 0g 0g 0mg 57mg 1g 0g
Heinz - Baked Beanz Bbq Sauce, 108 g 130 17g 1g 5g 0mg 504mg 7g 6g
Meal 4
Nuttab - Spinach Raw, 30 g 8 0g 0g 1g 0mg 0mg 0g 1g
Continental - Cucumber Raw, 50 g 4 1g 0g 0g 0mg 0mg 1g 0g
Nuttab - Onion raw, 12 g 3 1g 0g 0g 0mg 0mg 0g 0g
Nuttab - Mushroom Raw, 55.0 g 14 1g 0g 2g 0mg 0mg 0g 1g
Nuttab - Egg Plant Baked, 22 g 6 1g 0g 0g 0mg 0mg 0g 1g
Nuttab - Capsicum Raw, 25 g 4 1g 0g 0g 0mg 0mg 0g 1g
Generic - Raw Zuchinni - Skin on, 38 grams 6 1g 0g 0g 0mg 3mg 1g 0g
Chicken 100g - Chicken Breast Raw, 100 g 110 0g 2g 22g 0mg 63mg 0g 0g
La Barre - Caramelised Balsamic, 8 g 26 7g 0g 0g 0mg 0mg 0g 0g
Coles Bakery - Stone Baked Light Rye Sourdough, 30 g 69 14g 0g 2g 0mg 119mg 0g 0g
Christis - Halloumi Lighter, 43 g 108 1g 7g 11g 0mg 0mg 0g 0g
Maxs - Muscle Meal Protien Bar, 85 g 315 34g 6g 31g 0mg 240mg 25g 0g
Nestle - Milo Starz, 20 g 76 14g 1g 2g 0mg 23mg 6g 2g
Nestle - Milo Snack Bar, 1 bar 76 15g 1g 1g 0mg 20mg 5g 2g
Nuttab - Strawberries, 100 g 19 4g 0g 1g 0mg 0mg 0g 3g
Pb2 - Pb2 Peanut Butter, Powdered, 1 tablespoons 23 3g 1g 3g 0mg 47mg 1g 1g
Ferrero - Nutella (Aus), 10 g 52 5g 3g 1g 0mg 0mg 5g 0g
TOTAL: 3,313 304g 68g 343g 0mg 2,045mg 89g 41g
Total Calories: 3300kcal
  • Total Protein: 350g
  • Total Carbs: 300g
  • Total Fat: 70g
  • Total Fibre: 40g
Within this diet they are consuming:
  • 30g of whey
  • 200g of yoghurt
  • 50g of cottage cheese
  • 500g of beef mince
  • 300g of turkey mince
  • 100g of chicken breast

Totalling 900g of meat and 280g of additional dairy derived proteins.

They are also consuming:
  • 200g of mixed fruit
  • 730g of mixed vegetables
  • 70g of oats
  • 100g of pasta


As you can see there is a TONNE of mixed vitamins, nutrients and fibre from varying food sources, which provide all the necessary vitamins and minerals required for physiological and psychological health.

  • Keeping this in mind, should we really be concerned about the 10g of Nutella, 20g of milo cereal, the milo bar (30g) and the processed protein bar?
  • Likewise, is the 40g of halloumi a concern?
  • Why is it that cottage cheese is deemed good but other cheese is bad?
  • Have you ever actually asked yourself why people label foods?
  • Better yet, who even governs these decisions?
  • What constitutes a good, bad, clean or dirty food?


While some may look at the halloumi, milk, Nutella, cereal and snack bar on its own and deem them bad, or dirty foods, in the context of the entire diet they essentially play no negative role in metabolism, fat loss, physiological health or any other concern someone may have.

Instead, for this particular person who was in prep for a bodybuilding show and was approximately 8 weeks out, these foods provided a guilt free psychologically positive food option for them to consume in a time that they were restricted in food amount.

Above all, knowing that no food is 'off limits,' flexible dieting, especially in a caloric restriction phase, provides physiological, psychological and social BALANCE!

Don't get me wrong...
  • It is absolutely important to consume adequate healthy protein sources.
  • It is absolutely important to consume adequate healthy fat sources.
  • It is absolutely important to consume adequate fruit and vegetables
  • It is absolutely important to consume appropriate carbohydrate sources to maintain energy levels.

We can also consume small portions of the food we enjoy, in the context of an entire diet to ensure we maintain all three facets of dieting, which are physiological, psychological and social health.

Dieting is not about suffering to achieve a physical result at the cost of the other two factors but instead should be holistic in its approach to ensure health longevity is maximised. 

Flexible dieting is about balance, not abuse.

Dean McKillop

Exercise Scientist

I completed my Exercise Science Degree at the University of QLD and have worked in the fitness industry for over 8 years, including a short stint at the Brisbane Broncos in 2010 as a student. I also hold my Level 2 Strength and Conditioning Coach accreditation (ASCA) and have competed in 1 bodybuilding season, placing 2nd at the IFBB u85kg Nationals.

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