For decades, the number of calories you ate in a day was the end of the story. Stay in a deficit, and you’d supposedly lose weight. Slip into caloric excess, and you’d gain weight. That approach worked for some people, but for others, it proved limiting, miserable, and ultimately disastrous.
In reaction, a dietary approach called IIFYM, or “if it fits your macros,” has taken the fitness world by storm. Also known as “flexible dieting,” it turns old-school, restriction-based dieting on its head by focusing instead on monitoring individual macronutrient intake. As long as you hit certain numbers, there’s theoretically no limitation on what foods you can use to meet them.
Is it perfect and foolproof? Of course not. Though the basic idea of flexible dieting may seem simple, making IIFYM work as a lifestyle requires an advanced understanding of some key nutritional principles, because it can definitely be done wrong! But done right, it just might be the thing to help you stick with your plan more consistently than other approaches.
Whether you’re new to the nutrition side of things, or looking for a refresher, the information below will provide you with a thorough understanding of macros, splits, and IIFYM!