Am I Doing The Right Thing?

[Ratatouille]

Hi,

So I'm a 5'8" 160lb 19 yo woman wanting to lose around 10 lbs (but ideally more long term)... At the moment I'm running 4 times a week alternating between LISS and HIIT and I'm on a 1,000 calorie deficit. On days I don't exercise I'm burning ~2,000 cal and when I do it's more like >2,500. I was seeing some results both visibly and in my speed and feeling pretty good about it, but I've just done some reading into it and now I'm worried I'm going to lose muscle mass and that I'm being unsustainable. Is mixing up LISS and HIIT ok, or should I be moving away from cardio and more towards lifting (which I find very intimidating)? Is a 1,000 calorie deficit healthy for me in general? 

If anyone could help me out, it would be greatly appreciated!

[GershonSurge]

Don't worry about losing muscle mass. Muscle is mostly a function of our weight in the short term. Instead, worry most about percent fat as you lose weight or gain weight. Your exercise will take care of this.

I'll probably start a thread on body recomposition in a few days. 

[SunsetRunner]

Ideally, you should do both cardio and weight training. When people lose weight, it tends to be a mixture of fat, muscle, and water weight. To prevent muscle loss, you need to keep your protein up. You should be consuming 1-1.5 grams of protein per pound of body weight. If you’re only looking to lose 10 pounds, a 1,000 calorie deficit might be overkill. Find out how many calories you consume on average on a typical day. Calculate your macros from that. Protein should be 1-1.5 grams per pound of body weight, fat should be 0.5 grams per pound of body weight, and your carbs is based on calories you currently eat. Protein is 4 calories per gram, fat is 9 calories per gram, and carbs is 4 calories per gram. So currently at 160 pounds, you would need minimum 160 grams of protein (640 calories, based on 1 gram per pound of bodyweight), 80 grams of fat (720 calories), and for carbs take the number of total calories you currently consume and subtract the calories from protein and fat. That gives you how many calories you should eat for carbs. Divide that number by 4 to find out the grams. Gradually, you whittle away at the carbs decreasing carbs by about 50 grams at a time. Those numbers are not set in stone, so you may need to make adjustments based on how many calories you consume.

[Dominique]

Obviously someone very muscular is more at risk of losing lean mass when dieting down to a lower weight, but your concern is legitimate IMO, especially since your deficit is quite aggressive for someone your size looking to lose "only" 10 pounds. I would favor a slower pace, unless you have a special event coming soon for which you want to be leaner.

LISS and HIIT aren’t mutually exclusive. The main difference is LISS usually requires no / little recovery (so you can do it everyday if you want), whereas you should have rest days between HIIT sessions (if performed with the intended intensity). I personally think HIIT is overrated. If I were you, I would overcome the intimidation of weights and start lifting instead of doing HIIT sessions.