Male, 29, significantly overweight but fairly "solid."

I'm looking to get into a weight-loss regiment and I'm trying to figure out the best way to go. First of all, I bought an elliptical and will be using it regularly (at least 20 minutes a day interval training) and, of course, eating better.

For my weight-training, I'm trying to decide between two approaches -- my old routine from my younger days, and a new one that I've never really tried before:

1.) When I was younger, I would usually train to max out. I had a chest/shoulders/triceps day and a biceps/back/legs day. About 3 exercises per muscle group, 3 sets per exercise, 10 reps per set (or sometimes 10-8-6). I would use fairly high weights and work to failure. I would rest and stretch as much as needed between sets to ensure I could get through the next exercise

2.) Now, since my focus is fat loss, I wonder if it's better to try more of an aerobic circuit training. What I have in mind is 1 exercise per muscle group (maybe about 8-10 exercises total), transitioning from one exercise to the next rapidly with *no rest,* and then repeating the entire circuit as many times as I can within 20 minutes (upping the time and/or weight as I get in better shape). Obviously I would have to use lighter weights than my old system. I tried this last night and it really got my heart rate up.

Any opinions on which is better for fat loss? The 2nd one feels more "cardio" (continuous high heart rate, etc.) but I'm used to the 1st one and I imagine all that power lifting has its benefits even if I'm resting in between.

What do you think?

Thanks,
chris.

honestly, when cutting, I'm of the opinion that you should lift heavy, with lower reps.

reason being - a lot of muscle isn't advantageous from an evolutionary point of view. it slows you down, it requires calories to maintain, etc.
but if you lift heavy, you provide the stress needed to tell the body 'don't burn muscle, I still need it...see how hard my life is on my body?'
You'll want mostly compound exercises (the heavy lifts: bench press, squats, deadlifts, rows, military press, pull ups) and not a big split (either full body 3x a week, or a simple upper/lower or push/pull split). the goal is to maintain strength and lean muscle. you won't be adding any muscle because your calorie intake won't be sufficient for that. Heavy weight and keep the reps between 4-6...6-8 for lower body.

doing that in conjunction with cardio helps burn fat calories... either short, high intensity which appears to be your route, or longer less intense cardio like a brisk walk...which is better if your cardio is done upon waking, prior to eating. intense cardio on an empty stomach isn't a good choice.

the last part of this equation (again, this is my opinion which is based on my studies)...is watching your calorie intake...specifically carbs. carbs are what our body wants to use for energy. if you limit carbs and eat more protein and a moderate increase in fat intake form healthy sources, the body should attempt to convert stored body fat to usable energy.

I personally think carb cycling is a better option than restricting carbs all the time. really low carbs on cardio days, and about 1g per pound of LEAN body weight on weight training days. protein might be 2g per pound of LEAN body weight on cardio days so your calories don't fluctuate much...its a sliding scale between the two...and fat intake is fairly constant. keep it about 30% of your daily calorie intake with plenty of EFA's.

what he said ... left me with nothing to add

All you need to lose weight is to combine "vigorous exercise" and a caloric deficit diet. "Vigorous exercise" means different things to different people.