An expert in flexible dieting, aka "If It Fits Your Macros," explains the benefits and downsides of IIFYM, especially for lifters and athletes.
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In recent years, 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, calorie-based dieting on its head by focusing instead on the amount of protein, carbohydrates, and fats making up those calories. As long as you come close to your numbers (how close remains a subject of debate), you have a lot of flexibility on what foods you can use to get there.

| Should I Track My Macros? |
Not everybody needs to track their macronutrient intake. But plenty of people find that as their fitness and physique goals get more specific, dialing in their nutrition in this way helps them fuel their training and achieve better results. According to one expert, it can be helpful even if it's just a temporary experiment:

"I think everybody would benefit from tracking macros for at least a 3-6-month period of their life," recommends Dr. Bill Campbell director of the Performance & Physique Enhancement Laboratory at the University of South Florida, in an episode of the Podcast. "You just learn so much about making food choices, about overeating, undereating, and hunger. Someone might not change their behavior, but they'll know, 'Oh, that doughnut is a lot different than that chicken sandwich,' even though the calories may be the same."

| Does Flexible Dieting Work? |
A significant meta-study from 2020 concluded that the old-school model of restriction-based dieting, such as those that cut back on calories by minimizing carbs or fat, are largely ineffective for long-term, sustainable weight loss. This wasn't news to the thousands of frustrated dieters out there!

But is counting and balancing macronutrients any better? A study from 2005 comparing strict and flexible dieting found that people following a restrictive approach to dieting were more likely to have a higher BMI, reduced feelings of self-control, and more psychological stress related to weight and food intake. Chalk this up as another victory for IIFYM!

But don't think that just because a macro-based approach is "flexible," it's perfect. It has advantages and drawbacks like any other nutritional approach.

Thinking of trying it?'s Macro Calculator can give you the numbers you need to start right.

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00:00 - Tracking Macros
01:07 - The First Study on IIFYM
02:40 - IIFYM Study Results
04:10 - Critics of Flexible Dieting
05:55 - Don't Let the Scale Tell the Whole Story
07:32 - Anything is Better Than Nothing
08:45 - Scientific Studies on Weight Loss
10:00 - That Doughnut Is a Lot Different Than That Chicken Sandwich
13:08 - Flexible Dieting Just Feels Better
15:10 - Is Strength Training Essential for Flexible Dieting

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