Flexible dieting or IIFYM (if it fits your macros) – lively discussed, propagated and misunderstood.
Social media is filled with pictures of doughnuts, cakes, pop tarts, pizza and Co. This trend certainly counteracts the entire ‘clean eating movement’ telling us for years that we have to eat only healthy food in order to get a great looking body.
What is IIFYM?
The IIFYM principle is often misunderstood. Certainly, to some extent it is true, that following IIFYM one can eat whatever one wants, as long the total food amount one consumes is within the target calorie and nutrient (carbohydrates, protein and fat) range for the day. This is the point: nobody can eat tons of fast food all the time magically consuming the number of calories, that leads to weight loss, in case this is the desired goal. High calorie food has to be balanced out with low calorie food to hit the desired numbers of calories and macronutrients. Basically, if a person consumes the entire daily “calorie budget” in one meal, all the other meals have to be very low on calories (e.g. lots of veggies) in order not to exceed the daily target. What gives a wrong impression about flexible dieting is the fact, that most people rather prefer to post pictures of a stack of pancakes than a plate full of veggies.
Controversially, the most important principle of flexible dieting is making healthy food to the foundation of one’s diet to support the individual goals. In theory, the desired macronutrient and calorie targets can be met by a combination of sugar, protein powder and oil. Although, this food selection is theoretically possible, it is neither healthy nor recommended. For a healthy diet micronutrients (vitamins and minerals) and fiber are crucial, however lacking in the mentioned food combination. Fiber, acting as a prebiotic, is essential for a healthy gut microbiota composition, which is a significant contributor to our health.1 In most cases, adverse health effects are not caused by eating a certain food type or nutrient, but by not getting enough of other important nutrients. Occasional junk food consumption does not lead to obesity. The same applies to protein, it is most likely that it is not a high protein diet that causes all kind of diseases, but the lack of vegetables.2
Benefits of flexible dieting
For some people, flexible dieting is common sense and regulated by body’s natural mechanisms. In theory, the consumption of a high calorie meal should reduce hunger and increase the preference for eating a lighter, lower calorie meal later the day. However, it doesn’t work for everyone, in particular, because of psychological or psychobiological factors.
People who eat a high calorie diet (mostly high sugar and fat) have an altered hormonal response to food intake.3 Eating junk food on a regular basis has an addictive-like effect.4 Overeating on sugar and fat makes us craving even more of these nutrients and increasing our portion sizes. Going cold turkey and cutting out all calorie dense food at once is difficult, because of its addictive-like effect and not absolutely necessary. In this case, flexible dieting approach could help making the diet healthier by increasing the amount of lower calorie foods (such as veggies) and keeping the food one enjoys in the diet plan in reasonable amounts. It is very challenging to stick to a diet one hates.
Flexible dieting also is beneficial for people who follow a strict, calorie reduced diet regime. For instance bodybuilding competitors during contest preparations often feel deprived. This increases the chance of overeating or binge eating, once one is faced an unpredicted situation (e.g. food choice outside home) or when self-control is lacking. Everybody is stressed, tired or has a bad day from time to time challenging the will power to stick to a strict diet. Flexible dieting approach could help to avoid control loss in such situations. It prevents categorizing food into ‘good and bad’ or ‘allowed and forbidden’. By nature, most of the time we want the things we cannot get or are not allowed to have. Removing high calorie food from the ‘forbidden list’ will most likely decrease our desire to consume it whenever possible.
How to apply the flexible dieting principle
I already wrote one blog post on IIFYM some time ago. However, not giving concrete examples, I realized, that some people struggle with the application of this principle. For this reason, I would like to include an application example here. Let’s say, I would like to fit two Oreos into my healthy, balanced diet. Adding something that was not planned requires removing some of the initally planned food from my meal plan for the day.
Two Oreos have the following approxiamate nutritional composition:
106 kcal, 15g carbs, 1g protein and 4.5g fat
As Oreos mostly consist of carbohydrates and fat, I need to remove a carbohydrate source (e.g. fruit) and a fat source (e.g. nuts) from my diet in order to compensate for the consumed Oreos.
For example, four almonds and one small apple could do the job:
4 almonds (8g) – 50 kcal/ 0g carbs/ 1.5g protein/ 5g fat
1 small apple (100g) – 53 kcal/ 13 g carbs/ 0g protein/ 0g fat
total of which (103 kcal/ 13g carbs/ 1.5g protein/ 5g fat) is very similar to the nutrient content of two Oreos.
In some cases, it makes sense not only replacing some food, but also adding a certain nutrient. For example, when food with high protein content (e.g. tofu) was replaced by food with a different macronutrient distribution (e.g. pasta - high carb), it may become difficult to hit the desired protein target for the day. Here, the easiest option to ‘regain’ the removed protein without adding many extra calories is to consume a protein shake. Protein powder, as isolated macronutrient, is very convenient to make up for the missing protein.
Flexible dieting is not about eating cookies, cakes, pizza & Co. all the time and getting the body you want this way, except,
- you have serious problems to gain weight and this is your goal or
- you are a genetic freak who doesn’t gain weight or
- have a serious illness that prevents weight gain.
Everything is about balance and moderation. Demonizing entire food groups and eating only ‘super healthy foods’ is not particularly healthy for the mental health. Smart, not strict, is the motto here.
Interested in vegan, high-protein, guilt-free treats that fit your macos? Get your free recipe ebook by subscribing to my list ;-)
- Arora, T., Sharma, R. & Frost, G. Propionate. Anti-obesity and satiety enhancing factor? Appetite 56, 511–5 (2011).
- Schwalfenberg, G. K. The alkaline diet: is there evidence that an alkaline pH diet benefits health? J. Environ. Public Health 2012, 727630 (2012).
- Singh, M. Mood, food, and obesity. Front. Psychol. 5, 1–20 (2014).
- Schulte, E. M., Avena, N. M. & Gearhardt, A. N. Which foods may be addictive? The roles of processing, fat content, and glycemic load. PLoS One 10, e0117959 (2015).