I’m looking to reduce my bf% but I have quite bad asthma and cardio tends to aggravate it. Is it possible to reduce ones bf% purely using diet and weight training? Google is giving me conflicting information. Thanks.
Yes. Diet will always be the single most important factor of any weight loss plan. Cardio just makes it easier because it expends lots of calories and helps you burn more than you’re taking in.
Talk to your doctor about how to work with/around your asthma. Cardio is good for you.
Whole bunch of top athletes have asthma, David Beckham comes to mind for no apparent reason.
I speak to someone who really knows their stuff before dismissing cardio.
I have no problem losing weight without cardio. I do stick to a low carb diet, but I don’t focus on reducing calories or fat. I just lose my appetite pretty fast when I go very low carb for a week first. I do strength training every other day at the gym but that’s all the exercise I’ve gotten and my weight loss has been steady for the past few months. I lost 80 lbs. a few years back on the same plan.
I don’t know how people here feel about Mark’s Daily Apple but here’s a link to “A Case Against Cardio”: A Case Against Cardio (from a Former Mileage King) | Mark's Daily Apple
My eyes glazed over when he started talking about “primal DNA” and our hunter-gatherer ancestors. I skipped to the end and found the expected advertisement for a miracle pill.
Thanks for your answers everyone. It’s much appreciated. I’m hoping to get my bf% to around 10-12% (it’s around 20% at the moment). I know it won’t be as easy without high intensity cardio but so long as it’s possible I’m happy 
20% is already pretty lean, and 10-12% is ripped. Is that what you want?
That’s very low - past what the American Council on Exercise would classify as “fit” and into the “athlete” category.
Again, speak with your physician about the right way to approach this. Reasonable goalsetting is incredibly important for any sort of fitness plan.
Yup. I’m going on a beach holiday 
Missed the edit window: As I understand it (and I freely admit I may very well not, I’m a total newbie when it comes to all this) creating a calorie deficit through diet alone prompts the body to burn fat and muscle for fuel, but adding weight training gives your body an incentive to preserve the muscle, thereby burning mostly fat. Is that roughly correct?
This is all true, but ‘cardio’ doesn’t mean you need to run or spin or whatever is popular. Walking is essentially as good an exercise per unit distance as running, is easier on your joints, and weighted walking (a.k.a. rucking) is an excellent fat-burning exercise which you can mediate effort to prevent an asthma attack.
Mark Sisson has some excellent fitness and dietary advice mixed in with a bunch of neo-paelo philosophy that uses unsubstantiated theories and pseudoscience as well as actual research, and it is often difficult to tell which is which. The reality is that you don’t need supplements if you don’t have a specific vitamin or mineral deficiency and are eating a healthy diet with the correct balance of proteins and ‘good’ fats along with the requisite amount of carbohydrates commiserate with your activity level. And there is no reason to ‘diet’ in such as way to be hungry all the time as long as you eat food that provides good satiety.
Essentially yes. Different people have different basal metabolic levels (governed to some extent by the amount of lean mass but also by the insulin response to diet), and if you just cut away calories alone your body turns to muscle mass because it is easy to break down. One important thing to note is that if you are building and maintaining muscle mass, you need a certain level of carbohydrates to process dietary protein, and you need good fats for structure and sterol production, so the notion of a low carb or low fat diet is inherently unsustainable. On the other hand, a well balanced diet which avoids too much processed sugar and carbohydrates (basically, anything baked, or that comes in a bag or box) and a moderate amount of regular exercise, along with avoiding a sedentary lifestyle (sitting at a computer or on the couch for hours on end) will allow you to naturally moderate your body composition. However, getting down to a 10% body fat is taking that to an extreme, and you’re definitely going to need to alternate muscle building exercise and restricting caloric intake to get there.
Stranger