IIFYM or flexible dieting: the rules, benefits and risks

Diet is IIFYM stands for if it fits your macros, meaning if it fits into your macronutrients. The essence of the diet, which is also called flexible, is to count macronutrients, not calories that humans consume.

In contrast, diets associated with various limitations, supporters describe it as IIFYM flexible diet that helps people lose excess weight without major changes in dietary habits. We will talk about the basic rules of flexible dieting, as well as its potential benefits and risks.

What is IIFYM or flexible dieting?

The IIFYM diet is based on the idea that to consume lesser calories than required by the body (at the same time, consuming adequate amount of proteins, carbohydrates and fats) leads to weight loss with a steady and predictable rate.

People who adhere to a flexible diet, watching the number three macronutrients

  • Proteins
  • Carbohydrates
  • Fats

To the group of carbohydrates also include cellulose.

People can consume these nutrients in various combinations if the number does not exceed the daily needs of the body. This means that if the balance of each group makroelementov has not reached the acceptable level, the person can eat any kind of food, continuing to achieve their goals in health and beauty.

Where to start?

Adherence to a flexible diet:

  • Count the number of calories needed to maintain your current weight
  • Determining the number of calories which must be reduced for desired weight loss
  • The grouping of these calories in the macronutrients: proteins, carbohydrates and fats

Goals and numbers vary depending on factors such as age, gender, weight, height and activity level. Use a calculator on the website IIFYM or follow these steps:

Step 1: Calculate your current calorie needs

Basal metabolic rate (BMR) or the rate of metabolism at rest is the amount of energy in calories needed by the body during a 24-hour stay. This energy is needed to maintain basic functions such as breathing, blood circulation and body temperature.

The easiest way to determine your BMR using specializationin calculator. To perform the calculations manually, use the following formulas:

  • For men, BMR = 10 x weight (kg) of 6.25 x height (cm) – 5 x age (years) 5
  • For women, BMR = 10 x weight (kg) of 6.25 x height (cm) – 5 x age (years) – 161

Step 2: Adjust the caloric needs of a given activity

The next step involves taking into account the average level of physical activity, as this affects the number of calories spent by the body. This pokazatelyami your total daily energy expenditure (TDEE).

Calculate your TDEE using an online calculator that automatically takes into account BMR. The web site also provides the IIFYM TDEE calculator.

Step 3: Adjust calorie needs to achieve your desired weight

Subtract 15-20% from TDEE to find out how many calories you should eat per day to achieve their goals of weight loss.

Step 4: Determine the daily requirement of macronutrients

The last step is to divide the resulting value by the fact that the web site calls the adjusted macronutrients. Thus, you will be able to determine how much of the macronutrients required by the human, based on his current body weight:

  • Protein: it is considered that 500 g of body weight requires about 0.7-1.0 g protein
  • Fats: it is considered that the 500 g mass of a person is required of 0.25-0.4 g fat
  • Carbohydrates: this value shows the remaining calories from adjusted macronutrients

To follow the IIFYM diet, one must determine how much it consumes macronutrients at every meal and track your daily consumption to make sure that it does not exceed the maximum allowed. For more precise results, you can consider using digital scales to weigh food.

Many recipes with a description of the macronutrients available in the Internet. On the web site IIFYM presents a number of meal plans, including breakfasts, Lunches, dinners, snacks and desserts.

The benefits of flexible dieting

Possible advantages of the IIFYM diet include:


Two basic principles of flexible dieting is no restriction and starvation. It is offered as a more flexible meal plan, because it allows you to consume more variety of products than many other diets. This means that food may be more diverse, the main task is not to exceed the plan macro.

The purpose of the IIFYM diet is to make meals a little more varied, and meal planning not as difficult. This gives you the ability to stick to your diet in the long term.


Weight loss begins when a person burns more calories than it consumes.Usually this effect is achieved by reducing the daily amount of food on 500-750 calories. Flexible diet just use this method.

Similarly, the increase in calorie consumption leads to weight gain. People who want to increase weight, also can achieve their goals with flexible diet.

Diet can be useful for people who for whatever reason are unable to train

Since the flexible diet takes into account the levels of physical activity when calculating macronutrients for people who have physical limitations or can’t do the exercises, it can be extremely useful.

Risks and warnings

A flexible diet may have the following disadvantages:

Not considered micronutrients

Micronutrients such as vitamins and minerals, as important for health and beauty as macronutrients, but diet is IIFYM does not account for their consumption.

The body does not produce micronutrients, so people must get them from food. People who adhere to a flexible diet, can receive vital nutrients. According to the Centers for control and prevention of diseases, more than 2 billion people worldwide have deficiencies in nutritional minerals.

Macro calculations are not flexible

Some may experience difficulty adjusting to their needs in macronutrients such changes as illness, recovery after injury and breast feeding. For example, studies show that after illness the body requires more calories and protein, namely the 1.5-2.0 g of protein per kilogram of body weight per day to compensate for weight loss and speed up recovery.

Despite the fact that many recommend diet IIFYM flexible method of weight loss, available research is insufficient for scientific evidence of its effectiveness.

The diet is based on counting macronutrients (proteins, carbohydrates and fats) instead of calories. However, those who adhere to this food plan, you should pay special attention to the consumption of sufficient amounts of micronutrients such as vitamins and minerals.

In order to achieve the best results and to ensure the safety of your chosen diet, we recommend consulting with experts.