One Workout to Rule Them All 💪
There's a downside to losing weight that people don't always talk about: when you lose weight, you don't just lose fat. You lose muscle too. It happens on basically every diet, at every age, and it's one of those things that nobody mentions until you're 15 pounds lighter and wondering why you feel weaker. You did everything right and your body responded by eating itself. Cool. Great system.
A new study published in Maturitas wanted to know if the type of exercise you do while losing weight can change what your body decides to get rid of, and the answer turns out to be pretty clear.
Researchers tracked over 120 adults in their 70s across 6 months of supervised gym workouts, 3x a week, at different intensities. All three groups lost body fat, which is the headline everyone wanted. But only the HIIT group — high intensity interval training, comprised of short bursts of hard effort alternated with recovery — kept their muscle mass while doing it. The moderate and low intensity groups technically lost weight. They also technically lost the thing that was going to help them keep it off, which is like quitting your job to reduce your commute. 🤡
And this isn't just an aging thing. A review of weight loss studies found the same pattern in adults aged 18-30 — HIIT was the most effective exercise for burning fat while holding onto muscle. A separate trial of adults aged 25-50found that adding HIIT to a calorie-restricted diet completely prevented the muscle loss that the diet caused on its own. Same food, same calorie deficit, but the HIIT group kept every ounce of lean mass while the diet-only group watched theirs disappear alongside food that tastes good and the body fat they were actually trying to lose.
Why muscle is the thing worth protecting
Muscle burns calories while you do absolutely nothing, which is the kind of arrangement most of us would sign up for twice. It supports your joints, keeps your metabolism from tanking during a diet, and it's one of the strongest predictors of how independently you'll move through your 60s, 70s, and beyond. When you lose muscle during weight loss, your resting metabolic rate drops, you burn less at rest, the weight comes back easier, you diet again, you lose more muscle — and each lap around that track gets a little worse. It's a merry-go-round of sadness. 🥲
HIIT breaks that cycle because the intensity calls dibs on the muscle. Your body still burns fat — enthusiastically, even — but it leaves the lean mass alone because it just got a very convincing reminder that the muscle is still being used for something important, like surviving the last 30 seconds of an interval that felt longer than our country's history 😅
What this means here
We've written about HIIT before — the heart benefits, the brain data, the fat-burning efficiency — and we've also written about what happens when you overdo it, because there's absolutely a ceiling and ignoring it is how you end up taking an involuntary week off. But this muscle preservation finding adds a reason to include some high-intensity work that we haven't talked about yet: it's not just burning more, it's keeping the parts that keep everything else running.
If you've never done HIIT or you're not sure where your ceiling is, our trainerscan build something that matches where you are right now. We've also got group HIIT classes for some shared catharsis. You don't need to walk in already fit — you just need to be willing to breathe hard enough that small talk becomes genuinely impossible for a few minutes at a time, and the rest takes care of itself.
Helping you HIIT it with your best shot,
Your West Coast Fitness Family
P.S. Alyssa Cooks' Trailhead Training free info session has been moved to Sunday, July 13th at 5:30pm due to the holiday weekend. Come learn about the hiking and backpacking prep program, meet Alyssa, and see if it's for you. Details at the front desk 💪
