What is it?

IIFYM, also known as Flexible Dieting, is the ultimate tool in which to guarantee a successful diet. It is labelled as a diet, but it should be viewed as more of a dietary tracking system that bases its success around flexibility. Many diets are meticulous about which foods you can and can’t eat, and when you can consume them, which for many people can be a recipe for failure due to the excessive restrictions.

IIFYM goes against these common dieting trends, instead focusing on setting daily nutrient targets where users have control of their food choices, so long as the nutrient content of the foods does not exceed these targets. More specifically, the nutrients tracked are those that contain energy and directly contribute to body composition: protein, carbohydrates, and fat (and alcohol). These nutrients make up an individual’s total energy (caloric) intake:

1 gram of protein = 4 calories
1 gram of carbohydrates = 4 calories
1 gram of fat = 9 calories

workout frequency

The caloric intake and nutrient targets are adjusted based upon a person’s metabolic rate, current goals (lose/maintain/gain weight), and personal preference for different nutrient ratios. For IIFYM to work effectively, you must know your “maintenance calories”, which is the number of calories needed per day to maintain your bodyweight. Based on this number, you can adjust caloric intake to suit your goals. As a general rule of thumb:

Lose weight = Maintenance calories minus 500

Maintain weight = Maintenance calories

Add weight = Maintenance calories plus 100-300

As you may have realised, the concept is based off energy balance, the only consistently proven physiological determinant of weight control. As your body is a system of energy, negative energy balance leads to weight loss, and positive energy balance leads to weight gain. The breakdown of nutrients based on caloric intake is calculated and set by the user, mainly determined by the preference of whether an individual opts for a high carbohydrate or high fat diet (or moderate everything!). Below are some examples of how different nutrient ratios can be used to achieve the same energy intake:

  • 50 grams of fat = 450 calories
  • 400 grams of carbohydrates = 1600 calories
  • 150 grams of protein = 600 calories

= 2650 calories

  • 135 grams of fat = 1170 calories
  • 50 grams of carbohydrates = 200 calories
  • 320 grams of protein = 1280 calories

= 2650 calories

Food databases, such as Myfitnesspal, are used to make tracking easy. Simply search for the foods you want to eat, enter the weight or quantity, and if nutrient targets are not exceeded, you can eat it. To many people’s surprise, you can have some junk food whilst still losing weight! IIFYM throws out the idea of “clean vs dirty” foods or “healthy vs unhealthy”, as body composition is only affected by energy balance and caloric intake.

Musclefood protein pizza

The Benefits

1) No food is banned – This is the most obvious advantage of IIFYM. No longer will you constantly be saying “O I wish I could eat some chocolate and a slice of pizza”. Cravings can be satisfied, as long as you aren’t ploughing through tubs of ice cream and smashing through your nutrient targets. IIFYM is about numbers and basic physiological principles. As long as you stay within your caloric limitations you have no need to feel guilty to have the odd treat. This is more likely to lead to a sustainable, long-term dietary commitment.

2) No more social awkwardness – Finally you will not have to inform your friends or family that you are unable to join them for a birthday meal, or having to stick to the plain garden salad with no oil. Most restaurants, especially chain restaurants, have all their food and nutritional profiles updated onto food databases. Although tracking calories and nutrients when eating out may result in more inaccurate nutrient tracking, as you are not preparing the food, it is perfectly acceptable to do on a semi-regular basis. However, it is advised to check the menu and nutritional profiles before you enter the restaurant as you don’t want to accidentally order a meal with an extraordinarily high fat/calorie content which might ruin your nutrient targets.

3) No more plateaus – Many diets are strict plans that ensure energy deficits and ultimately fat loss by severe restrictions. The problem is that the body will eventually adapt to the energy deficit, and progress will stall. Strict plans that allow no flexibility or user control are not able to be adjusted to further decrease energy intake and continue fat loss. IIFYM tracks everything you consume, and it is simple to adjust your nutrient targets to create a renewed energy deficit once progress has stopped. The ability to manage and manipulate dietary intake in such a specific way is unique to IIFYM. You do not need to rely on whether the diet is “working”, you are in control.

4) Bulking is controlled – A common trend for those looking to put on weight and gain muscle is to have an “all or nothing” approach, eating everything in sight to satisfy the “gains”. The mentality of weight gain can often lead to extremes, unless well-disciplined, and will lead to rapid weight gain (mainly fat). IIFYM gives you a controlled approach, where you are able to determine and track the rate at which you add weight. IIFYM allows you to be precise and create a slight caloric surplus that will lead to a better ratio of muscle to fat gain.

protein cupcakes

The Cons

1) Health is placed as second best – IIFYM has a clear focus on altering your body composition, and the emphasis is not necessarily on making “healthy” food choices. As you can make progress in terms of fat loss or muscle gain whilst eating “junk food”, many people take this to levels where it causes detrimental health effects. The emphasis is not placed on reaching your recommended daily amounts of vitamins and minerals with the consumption of a variety of fruit and vegetables. Users should still aim to eat mainly whole, unprocessed foods with minimal salt, sugar and saturated fat content, that are rich in antioxidants, vitamins and minerals. Energy levels and general wellbeing may be affected unless users still make an effort to make good food choices. Eating treats should be looked at as a possibility when cravings are high, rather than the base of the diet.

Who should run this diet?

IIFYM is great for people willing to track their food intake to make significantly better progress. Typically, the diet is utilised by bodybuilders or fitness enthusiasts who want complete control of their bodyweight and are interested in the finer details. Some people may find the idea of inputting foods into a database a few times a day rather strange and extreme. It is really based on how far you are willing to go to reach your goal, and your perception of what is too much and what is not.

women exercising

IIFYM may also be necessary for those who are not capable of sticking to a stringent eating plan that has many restrictions. If you are someone who finds IIFYM extreme, but you also have a serious goal you want to reach and fail to stick to other plans, it might be your only option as it guarantees success.

IIFYM is not built for users that need a step-by-step meal plan to incorporate into their daily routine. Just like some people will only go to the gym if they have a personal trainer by their side telling them what to do, the same mentality can be seen for a diet. Even though IIFYM is built for simplicity to ensure long-term commitment, some individuals might find meal plans or dietary restrictions a simpler, more convenient method.