To lose a lot of fat mass, should I lift weights, do cardio, or both?

Question

I'm 6'0 and 272 lbs. I'm 43 and have always been a big guy i.e in 1st grade I was over 100 lbs. already.

According to my fancy scale, it says I have 30% body fat so my goal is to lose 80lbs starting today.

I understand that I need to eat less but when I go to the gym from here on out, should I focus on muscle building since muscle burns more fat or should I just work on 30-45 min. walks/jogs to lose the fast.

I can get to the gym 3x a week for up to 45 min. each time, what would be your best suggestion to make efficient gains in your mind?

Answer 1

The main issue with losing weight through exercise is that your body has mechanisms for counteracting calories burned through exercise. That means that those extra calories you burn from the increased metabolic activity of muscle are likely to be precisely compensated by increases in appetite and decreases in your metabolism. So unless you're rigorously counting calories, you're likely to eat more, and not lose any weight at all. (Of course any exercise is likely to make you healthier.) What you need are activities and lifestyle changes to alter your body mass set point, making your body "want" to be thinner.

There's some evidence that you should focus on High Intensity Intervals Exercise/Training to maximize fat loss. This small study found that the following (SSE means something like standard "cardio"):

Results: Both exercise groups demonstrated a significant improvement (P<0.05) in cardiovascular fitness. However, only the HIIE group had a significant reduction in total body mass (TBM), fat mass (FM), trunk fat and fasting plasma insulin levels. There was significant fat loss (P<0.05) in legs compared to arms in the HIIE group only. Lean compared to overweight women lost less fat after HIIE. Decreases in leptin concentrations were negatively correlated with increases in VO2peak (r=−0.57, P<0.05) and positively correlated with decreases in TBM (r=0.47; P<0.0001). There was no significant change in adiponectin levels after training.

Conclusions: HIIE three times per week for 15 weeks compared to the same frequency of SSE exercise was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance in young women.

In other words, high intensity intervals led to increased fat loss, and increased some measures of insulin sensitivity. Here's a link to a few more studies, with promising results.

That said, HIIT can be quite difficult, probably more difficult than standard cardio or many types of strength training. So while I'd recommend trying HIIT, don't let the perfect be the enemy of the good: the best exercise is the exercise you do. Giving up on an exercise program burns 0 calories.

Another aspect to consider is ancillary benefits. IMHO, improving strength and flexibility will make you feel better faster than cardio or HIIT. Strength training can improve pain of various sorts (especially back pain) and make it easier to start other kinds of exercise programs.

Answer 2

I would recommend a multipronged approach, actually. You are correct that muscle burns more than fat, and that is where I would start. Take a look at a good weightlifting program such as Stronglifts 5x5, which will give you an excellent muscle building base. As you build the muscle, you'll contribute to fat loss as it will require more calories on a daily basis to maintain.

As far as the dietary approaches go, you are correct that eating less will help, but you also need to look at what you are eating. It does no good to put the time in at the gym, if all you are going to do for your diet is go from 2 Big Macs at lunch to 1. I would slowly shift your eating to a more healthy structure. You will want somewhere between 1-2 grams of protein per kilogram of body weight per day. (Kilograms is pounds/2.2, 176 lbs is 80kg). I say slowly, as suddenly switching your entire diet is likely to create cravings that undermine your efforts and promote binge/splurge eating.

As part of this, add small salads and healthy soups to your main meals, and eat them before the main meal. This will help curb appetite, and suppress the urge to overeat. Also, eat a bit slower. The "I'm full" feeling is controlled by stretch receptors on the stomach walls, and the signal can take a few minutes to get to the brain. If you are shoveling in food as fast as you can, this can lead to overeating. I wouldn't worry too much about following this diet or that diet, but aim to get around 20% of your calories from healthy fats, another 30-40% from lean proteins, and the rest from healthy carbohydrates (The less refined the carb, the better.)

Start a food log. Learn to weigh your foods, and accurately count calories. Aim for 1-2 lbs of loss per week. In the beginning you will probably lose a little faster, later it will be harder. Don't be discouraged, it will eventually come off. If you need to, find support channels (Such as exercise groups, friends, here), as going it alone can sometimes get discouraging.

I would also add cardio. You don't have to go to the gym, and at the beginning, it can be as simple as a 10 minute walk. This will also help with caloric burn and metabolic increase, and is easy to do every day.

You will have ups and downs, there will be days when you will cheat (Which is perfectly find), but if you stay with it, eventually the weight will come off, and all along the way you will be getting healthier and more fit.

And finally, it sounds like you have been somewhat heavy most of your life, so as a precaution I would schedule a visit with your family doctor. Weightlifting and various cardio exercises can cause quite a spike in blood pressure and heart rate, make sure you're healthy enough to do what you intend to start.

Answer 3

Both cardio and weightlifting play vital roles in weight loss. Weightlifting helps as you mentioned, by building muscles which in turn burns more calories over the course of the day even when you are not in the gym. Cardio on the other-hand is a great way to burn calories in bundles in one workout. Your problem seems to be that you only have 3 days a week that you can get to the gym which doesn't allow to work cardio on the days that you are not lifting.

Because of the above I would really recommend doing HIIT type workouts. High intensity interval training allows you to burn a lot of calories while you workout and also build some muscle which will help you burn calories even when you are out of the gym. Now obviously this won't build as much muscle as as would a regular weightlifting session, but given the fact that you have a goal of losing FAT and not WEIGHT and only having 3 times a week to workout I think that this is your best bet.