For my first post, what better place to start than addressing what If It Fits Your Macros (IIFYM) or ‘flexible dieting’ actually is. This is one of the most widely adopted practices of achieving your goals used in current times and can yield great results. Backed by many people such as Layne Norton it has continued backing from prominent athletes and fitness personas.
The basic principle behind IIFYM is that every individual has their Basal Metabolic Rate (BMR) from which they can find their Total Daily Energy Expenditure (TDEE) based on factors such as their activity levels, job, height, gender and age. With this information you can then adjust your calorie intake according to what your goals are. At a basic level it is simple, if you want to lose weight, your calories in need to be lower than your calories out, adversely if you want to gain weight your calories in need to be higher than your calories out, Fulfil this criteria and you absolutely will gain or lose weight.
The changes start once you have identified your caloric needs and have chosen your goal or target. Lets take the example of somebody that is looking to drop their body fat percentage whilst maintaining strength. Lets start by giving the individual an identity, lets say
Male
25
180 ibs
6ft tall
With that information, if their theoretical TDEE was 2600 calories, to drop body fat they would need to lower their calories to around 2400 to begin with, and if weight loss slows, perhaps reduce it further. It is important to remember however the main objectives whilst entering a caloric deficit. The main goals are
– Preserve Strength and Muscle
– Lose Body Fat
– Maintain your intensity in the gym
With those goals in mind you can begin to fill out your macro nutrient requirements within your calories. It is widely accepted that whilst on a cut, depending on your body type it is best to hit around 1 gram of protein per pound of body weight, meaning 180 grams of protein which amounts to 720 calories as there are 4 calories per gram of protein (180 x 4 =720).
Fat is something that should not be neglected, low fat levels can have a negative impact on your hormone production and health fats such as Nuts, Red Meats, Healthy Oils and some Dairy Products should be part of your diet. This individual may want to consume .4 grams of fat per pound of body weight which would amount to 72 grams of fat, however it is important to remember that unlike Protein and Carbohydrates which contain 4 calories per gram, Fat contains 9 calories per gram. This means 648 of this individuals calories would be assigned to Fats.
All this leaves is Carbohydrates, when cutting the Carbs are the macronutrient that should be assigned last, however are still very important to maintain similar intensity in your workouts. Once you have your Protein and Fat intakes set, the rest will be for Carbohydrates. This individual has already consumed 1,368 calories which leaves them with 1,032 calories to assign to Carbohydrates which, as there are 4 grams of Carbohydrates per calorie would amount to 258 grams of Carbohydrates, meaning this individuals macronutrient breakdown would look like this.
Calories : 2400
Protein : 180 grams
Fats : 72 grams
Carbohydrates : 258 grams
This would be a good starting point but after a couple of weeks, it may be beneficial to make small changes to maximise the efficiency, perhaps reducing some of the calories taken in by Carbohydrates to increase either the Protein or Fat intakes. Which leads us to the conclusion and what many consider to be the main draw of IIFYM, as long as you hit those numbers, you are free to consume what you like, meaning that you can have a chocolate bar or burger from time to time as long as it hits your macro nutrient requirements. Now obviously it is still important to fill your calories with foods that are micro nutrient dense such as fruits and vegetables as the macro nutrient profiles are what will effect your body composition, however your internal health is dictated by the vitamins and minerals found within ‘healthy’ foods.
This is a basic explanation of the idea behind IIFYM, which is the approach i currently take to my nutrition, it is important to remember that this post is meant to be informative and give an insight into what the practice of IIFYM is, and thus hopefully it has done so! Keep locked for more content
BTF.
bthurstonfitness 
Hey BTF, thanks for sharing this information. I have a couple questions…
1) that seems like a lot of protein (1g/lb); what is the science/rationale behind that?
2) how do you recommend someone ascertain their basal metabolic rate? There are so many calculators online for this, but they each seem to give slightly different results. Do you recommend a particular one?
3) when eating ad lib, do people tend to eat more overall calories than their basal metabolic rate requires? Or are we wired to consume EXCESS calories? In other words, would it take a conscious, disciplined effort against instinct to eat only as many calories as I burn?
I’ll be following!
Best,
DH
Hi Derek
No problem, firstly as fas as protein goes, it depends on your goals but as mentioned, if your simply trying to lose weight and aren’t too concerned with your body composition or muscle mass then 1 gram of protein per pound of body weight will be quite high however if you are trying to maintain muscle mass, you will need that amount of protein to stop the body from going to the muscle for energy when you’ve used up the carbs and fats as your in a caloric deficit. I’d recommend looking up ‘Layne Norton’s guide to cutting’ for a more in depth explanation but as said, it depends on your goals.
The calculator i’ve always recommended and used can be found here
http://iifym.com/iifym-calculator/
I’ve always used this and had success with it, it’s important to just remember that it is an estimate so whilst it will be fairly accurate, it make take a few weeks of tweaking to fully get it on point. Try it for a week, if you lose a pound keep at it, if not, take the calories down by another 100.
For the last point, i know exactly what you mean! ad lib or boredom eating is a habit that you don’t even realise your doing most of the time! If you make informed choices then yeah of course you can come under your requirements. Consume foods that are high in volume but low in calories so Blueberries, Strawberries, vegetables, strained yoghurts and things like that. Foods high in fat like chocolate bars crisps and things like that are where your going to build up lots of calories in small amounts of food, not to say that i don’t eat them at all i enjoy them in moderation. I’d recommend taking a look at the ‘MyFitnessPal’ app on andriod, iphone or your computer, i track my caloric intake through that so it know how much im taking in.
Hope this helps!
BTF