Here's the uncomfortable truth: most people training hard are still leaving results on the table, not because their workouts are wrong, but because they're eating blind. They track their sets. They track their reps. They never track the one thing that actually determines whether that effort turns into muscle, energy, and recovery, or just gets wasted.
That thing is macros.
The guys and girls seeing the fastest, most consistent progress right now aren't training harder than everyone else. They've simply stopped guessing at their nutrition. And once you understand what macronutrients actually do inside your body, you'll wonder how you trained without knowing this for so long.
To build a nutrition plan that actually supports a sustainable fitness routine, the team at F45 is breaking down everything macros: what they are, what they do, and exactly how much you should be eating of each.
Macronutrients, or "macros," are the nutrients your body needs in large amounts to function and perform. There are three: carbohydrates, protein, and fat.
Here's the part that matters: your body doesn't produce enough of these on its own. It relies entirely on what you eat. Skip or mismanage one, and your body doesn't just shrug it off, it compensates in ways that quietly undercut your training.
Carbs are your most efficient energy source, which is why they matter most for endurance work and high-intensity conditioning. Fat and protein can also be converted into energy, but only after your carb stores are depleted. Your body prefers to save fat and protein for other jobs, cell function, hormone production, and muscle recovery.
This is the part most people never hear, and it's exactly why they plateau.
Under-eating carbs before a high-intensity session means your body runs out of stored glycogen mid-workout, forcing it to break down muscle tissue for fuel instead of building it. Under-eating protein means muscle protein synthesis, the actual process your body uses to repair and grow muscle after training, slows down or stalls entirely. Skip healthy fats, and hormone production takes the hit, including the hormones responsible for recovery and muscle growth.
The result: you keep training just as hard, but your results quietly flatten. Energy crashes mid-session. Recovery drags out longer than it should. Progress that should be showing up on the scale or in the mirror just doesn't.
If this sounds familiar, it's not your training. It's your fueling.
Protein rebuilds what training breaks down, and helps manage delayed onset muscle soreness (DOMS) after a hard session.
Carbs are your go-to for both quick and sustained energy, critical for powering through high-intensity training.
Fat supports cell growth, hormone production, and vitamin absorption, functions that directly affect how well you recover and build muscle.
Protein breaks down into amino acids, nine of which your body can't produce on its own. It uses these to repair muscle tissue, build enzymes that speed up chemical reactions in your cells, regulate blood pH, and even produce hormones that influence mood and appetite.
Carbohydrates convert into glucose, the fuel your cells, tissues, and organs run on. Extra glucose gets stored in your muscles and liver as glycogen, your body's on-demand energy reserve for training. Fiber from healthy carbs also supports digestion and keeps you full longer.
Fats break down into fatty acids that insulate your organs, get stored as backup energy, and dissolve fat-soluble vitamins like A, D, E, and K so your body can actually absorb them.
This is exactly why nutrition and training can't be separated. F45's 45-minute format pushes your neuromuscular, cardiovascular, and metabolic systems simultaneously, through resistance work, functional movement, and high-intensity conditioning. That kind of output demands the right fuel behind it.
Show up under-fueled, and even the best-programmed session leaves you running on empty. Show up with your macros dialed in, and the same session converts directly into strength, recovery, and results. The training creates the stimulus. Your macros determine whether your body can actually respond to it.
As a general guide:
Your goals shift the ratio. Building lean muscle? Increase protein slightly, trim carbs. Focused on fat loss? Reduce carb intake while keeping protein steady to protect muscle mass.
Every session you show up to is an opportunity, but only if your body has what it needs to use it. Dial in your macros, and you stop leaving results on the table. Find your nearest F45 studio and put your training and your nutrition to work together.
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