If you're not familiar with the phrase 'iifym' it stands for 'if it fits my macros', a craze that started being used by people competing in fitness physique competitions who needed to be of a certain weight/size but now had been adopted by a lot of gym go-ers.
It is a calculated daily amount of protein, carbohydrates and fats based on your weight usually and sometimes activity level..and yes there is a lot of science behind it that it will help to lose weight however it requires daily weighing of food/packet checking and/or entering it into a tracking device to make sure the correct quantities have been met.
A lot of people will say this approach to 'dieting' allows them to have what they want to eat (e.g. A biscuit) as long as it fits into their daily allowance. Sounds great huh? Well, that means there would need to be some compromise throughout the rest of the day.
My belief is that all food is to be enjoyed in a relaxed way, with a mindfulness on eating things that have a benefit to our health. Weighing food constantly and making sure it hits a certain number has taken away any intuitive approach you once had towards food. There then becomes a control with food-it's measured, it has to look a certain way on a pie chart - has this now taken away any care free approach to eating?
Are these people able to listen to their hunger cues and eat something they fancy rather than eating something because they need to increase their protein intake for example?
Eating is something we do for perhaps 3-5 times a day (depending on the individual), it shouldn't be something that is stressed over or constantly monitored. Is the iifym approach sustainable long term? Can weighing scales be taken to everywhere you go? Does every place you eat out at have their macros per dish online?
It might be an approach that works short term, but really restrictive and controlled by food might lead to longer problems and thoughts around food..