Flexible dieting, also known as IIFYM ‘if it fits your macros’ is an increasingly popular diet strategy that is based around some key, scientifically supported principles. Here we will discuss the pros and cons of flexible dieting and whether it would be right for you.
Firstly, whether we lose or gain weight will be governed by the number of calories we eat across the course of days, weeks and months. Our daily calorie allowance will be governed by our goals, there needs to be an appreciation of where those calories come from. There needs to be sufficient protein, carbohydrates and fats to help you reach your goals as each have slightly different impacts on the body in terms of fat loss, muscle gain and performance.
It might be that you simply choose your macros to reflect your preferred food choices, in terms of calories, these can be adjusted on a daily basis, one day you might have more fat, the next day more carbs, as long as you are within your allotted calorie intake (most people keep protein fixed) where you get these calories from does not matter.
As you can see, this allows for a lot of flexibility in the diet, it allows you to include a whole host of foods, even ‘junk foods’ can be included as long as you hit your daily calorie, protein, fat and carb intake goals. This is great for people who want to have a balanced lifestyle, as it allows them to eat out, socialise and have the occasional daily treat if that suits their eating habits whilst still following the fundamental principles that govern muscle gain or fat loss.
Unfortunately, flexible dieting can be abused. Occasionally ‘saving’ macros for a meal or special occasion is fine, but the temptation might be to do this every day, which leads to having a diet that lacks balance, variety and is devoid in essential vitamins and minerals, and this from a health perspective is something that needs to be considered from both a physical and mental view, especially if it encourages poor eating behaviours such as binging. Flexible dieting also does not emphasise things like meal frequency or meal timing, which for some may be important in terms of optimising sports performance, muscle building or fat loss.
There also needs to be an awareness of trigger foods; these are foods that can trigger overeating behaviour, to use a popular food brands slogan, ‘once you pop, you can’t stop’. It may seem great to be able to eat your favourite foods every day, but there still needs to be an element of self-control, which is the same on most diets. You also need to take into consideration things like food volume and how filling certain foods are. This is not such a big issue when looking to gain weight or for those lucky enough to be able lose body fat on high amounts of calories, but for those struggling with fat loss, food volume and calorie density is something to seriously consider to help control hunger and reduce cravings.
In summary, flexible dieting, if used in a sensible manner and is still inclusive of nutrient dense foods, is a scientifically supported and an effective way to allow people to have a sustainable approach to nutrition, which does not feel as overly restrictive as some ‘diets’. As with all diets, adherence is the key to success, hopefully we have outlined some of the key points to consider if using flexible dieting.
Paul Rimmer (BSc, MSc, PhD).
