IIFYM Diet is Good or Not?

IIFYM Diet is Good or Not?

The IIFYM, also called Flexible Diet, is a method of nutrition that many practitioners praise, but on which others shoot red. It is based on a simple principle: you can eat whatever you want as long as it meets your macronutrient needs. Let’s see if this method can help you progress or if it is only a fumistery as there are so many.

IIFYM Diet is Good or Not

How was IIFYM born?

The Flexible Diet originates in 2005. On an American nutrition forum, a practitioner came to ask for advice. He wanted to know if eating a banana could be useful in his diet, in order to consume more carbohydrates. A moderator from the site replied “If it fits your macros” (IIFYM). In other words: “Yes, if it goes into your macros”. This advice was then repeated many times and eventually culminated in a nutrition method, popularized on YouTube by people like Chris Lavado and Matt Ogus.

However, if the council may sound good, it is not interpreted in the same way according to the practitioners. This can lead to some form of food drift. We’ll see why.

The basis of the Flexible Diet

If we start with the basic idea, the IIFYM follows a simple concept: you need a certain amount of macronutrients and no matter what foods are absorbed to get them. It can be industrial food, fast food, pizzas, ice cream, etc.

From there, it’s very simple, you have to calculate your caloric needs and adjust them according to your goal. These needs vary depending on your weight, height, age, metabolism and physical activity. Suppose you need 2500 calories to keep a steady weight, you will need to eat a little more to take mass and a little less if your goal is to dry.

Next, you need to determine your optimal intakes of macronutrients, ie protein, carbohydrates and lipids. For proteins, it is considered that an intake of about 1.8 grams per kilogram of body weight is desirable for a bodybuilding practitioner. For lipids, 1 gram per kilo body weight is a good basis. The rest of the intake can be filled by carbohydrates. Obviously, these values ​​may vary, some people have a body that use better carbohydrates, others lipids, for example. Everyone must adjust according to his own case and knowledge of his body.

The advantages and disadvantages of this approach

By consuming the necessary amount of calories and the macronutrients your body needs, you should see results. Also, unlike a too restrictive diet, you should not suffer from frustration. This will prevent you from cracking and turning a bonus meal into bonus daytime, then weekday bonus, putting all your diet at risk.

Yet, this plan is flawed. He considers that macronutrients and calories can come, without distinction, from healthy and unhealthy foods. But, it’s a mistake. Unhealthy foods have many flaws. Some have a high Glycemic Index that stimulates too much insulin production. However, you should avoid too much insulin variation that can increase the risk of developing diabetes and promote fat intake. Other foods contain too much salt or are enriched with many additives, hydrogenated fats, etc. Ingredients that are not harmless for health.

So, of course, for some practitioners, this type of diet will not have any repercussions and there will even be a handful to get good results. But it is a minority. For others, it is better to apply the variant below.

The IIFYM’s other approach

Some IIFYM practitioners have thought this method of nutrition otherwise. Their strategy is to eat healthy about 80% of the time, that is, to consume basic, non-industrial foods, low Glycemic index, lots of fruits and vegetables, good fats, etc. On the other hand, for the remaining 20%, they allow themselves to eat less healthy foods that make them crave, as long as it is in their need for macronutrients.

This variant of the Flexible Diet is already healthier and allows to obtain results without too much frustration. She finally gets closer to what many other bodybuilding practitioners are applying: eating as well as possible, but allowing themselves to deviate from time to time.


Is the IIFYM a good feeding method? Yes and no. It all depends on how you apply it. If you think you can eat anything from the moment it comes into your macronutrient needs, then you’re on the wrong track. You need to take into account the long-term effects of this type of diet and its consequences on your health.

On the other hand, if you eat properly most of the time and you allow yourself a margin to eat some less healthy foods, the results will be much more positive.

Obviously, you could also eat well all the time, and make a bonus meal from time to time, if that does not make you crack.