Flexible Dieting is also sometimes also referred to as ‘If It Fits Your Macros’ Diet Approach, or IIFYM for short. They are largely similar but have a small difference. With both approaches, you get a diet where no food is restricted as long as it meets your macronutrient requirements. There are three key Macronutrients – Proteins, Carbohydrates and Fats. These three contribute to all the calories in your food and essentially by tracking your intake of these, you are also keeping an eye on how many calories you are consuming.
Popular amongst bodybuilders who are used to following a strict clean eating approach, this community realized that using the flexible dieting approach, they don’t have to completely exclude the foods they love, from their diets.
However, as things go, the extreme version of this diet became the reason for its popularity. The fact that you can have an eating plan that can max out on all your favorite foods, without feeling guilty of gaining weight – ‘as long as it fits your macros’.
But we are getting ahead of ourselves. Let us first understand more about the flexible diet itself.
The reason this diet is popular is that no food is out of bounds. You can eat doughnuts, pizzas, burgers or even chocolate and ice creams. This is also one of the challenges and shortcomings of this diet – you might end up compromising your health if you are not including fruits, vegetables and healthy fats in this diet.
Fruits and vegetables provide a lot of the micronutrients, i.e. vitamins and minerals, along with much needed fiber for a healthy gut and overall health. This diet needs a little bit of planning and a lot of calculations if you are not eating similar meals every day.
If you overindulge in chocolate and exhaust your carbohydrates for the day, your remaining food choices are going to be those that contain either very high protein (whey protein, skimmed milk, etc) and high fat (butter, oils, nuts, etc) or a combination of the two (cheese, cottage cheese, etc). The rest of day would not exactly be fun, right?
One upside to this style of dieting is that you will come out of this diet with a lot of knowledge about the macronutrient profile of your daily foods. This can be very helpful in the long run.
How is Rigid Dieting different from Flexible Dieting?
Rigid Dieting is when a person can only eat according to a specific meal plan and not eat foods outside of that meal plan. This can be psychologically stressful for some people and research suggest that Flexible Dieting might be a better approach for them.
Is Flexible Dieting Effective?
Evidence suggests that those following this approach can follow their diets for longer. This invariably gives better results (Stewart et al, 2002).
Who is Flexible Dieting Recommended for?
Flexible Dieting is a good option for those who want a little bit of freedom in their eating plan. Obsessing about eating healthy 100% of the time can also be detrimental to one’s health. Following this diet is very educational and once you get the hang of it, weight management can be liberating.
What are the foods one should not eat during Flexible Dieting?
There are no foods off-limits. However, it would be wise to include fruits and vegetables for satiety and meeting the minimum fiber requirements every day. Too much processed foods may lead to very high sodium intakes which can lead to high blood pressure and hypertension. Ideally, the meals should be balanced so that following this diet for a long period does not result in adverse health outcomes.
What are the challenges during Flexible Dieting?
Flexible Dieting requires a lot of planning and calculations. It is easier to adapt to when you start this with limited food items, and slowly add items that can give you the variety you crave.
Another important feature of this diet is portion control. If there is someone who has large appetite and cannot stop themselves after having only a little bit of chocolate or ice cream or any of their favorite foods, this diet is not ideal for them. For these people, completely avoiding the temptation foods might be a better way to start.
Can I lose weight on Flexible Dieting?
If the total calories consumed in the day are lower than your total daily energy expenditure (i.e. you are in an overall calorie deficit), one can lose weight on this diet. Research shows most participants followed it for longer and were more successful in losing weight, than those following rigid dieting. As you can see, weight loss is a result of being able to sustain eating in calorie deficit for longer periods.
So, any dieting approach that allows you to do that sustainably is the best approach for you. A study showed that rigid dieting or flexible dieting, the subjects achieved the same results as long as the calorie deficit was maintained at the suggested levels (Conlin et al, 2021).
No dieting approach is a sure-shot answer for losing weight. Approaches vary basis people’s lifestyle and habits.
What is that small difference between IIFYM and Flexible Dieting?
Flexible Dieting is a broader term that allows flexibility of different macro composition from day to day. Only two things need to be taken care of – the total calorie intake and the protein intake is above a certain threshold. Whereas in IIFYM, the macro intakes are fixed and need to be met daily.
What do I need to know to start Flexible Dieting?
You need to determine your goal – lose weight, maintain weight or gain. Basis this you can decide your calorie intake and divide that calorie over the three macronutrients – proteins, carbs and fats. Make a list of all the foods that you can eat daily and find their nutrition profile. For the first few weeks, you need to measure your food to learn how much you need to eat to meet your daily macro goals.
If you need help to understand how to create a diet plan, you can attend the free mission50M webinars conducted by INFS scholars or enroll into the short courses at INFS that will help you understand diet and exercise for long term health.
Author: Jyoti Dabas, Founder & CEO, Institute of Nutrition and Fitness Sciences (INFS)
References
Conlin LA, Aguilar DT, Rogers GE, Campbell BI. Flexible vs. rigid dieting in resistance-trained individuals seeking to optimize their physiques: A randomized controlled trial. J Int Soc Sports Nutr. 2021 Jun 29;18(1):52. doi: 10.1186/s12970-021-00452-2. PMID: 34187492; PMCID: PMC8243453.
Stewart TM, Williamson DA, White MA. Rigid vs. flexible dieting: association with eating disorder symptoms in nonobese women. Appetite. 2002 Feb;38(1):39-44. doi: 10.1006/appe.2001.0445. PMID: 11883916.
