Scientific studies and the "best exercise"

As a former math/science type, I certainly don't discount the value of empirical, scientific research. At the same time, I think it's useful to recognize the limits of such research, at least in the short run, before the usual process of science, which is to say, attempted replication/falsification of the initial study occurs enough that the results are considered not to be a fluke, and to reflect careful elimination of other possible explanations.

This is often true in the realm of exercise and health-related studies, where press releases trumpet the latest surprising finding, and which the mass media accepts uncritically for all that the study could be worth, as opposed to the least that it can be said to confirm.

For example, last week, the British paper The Telegraph reported that, per a new study, "weight training is better for your waistline than running." Note the specificity of the claim: it's not that weight training is better at producing weight loss, but at slimming the waist. Now, let's take a look at the study's press release and abstract:

Healthy men who did twenty minutes of daily weight training had less of an increase in age-related abdominal fat compared with men who spent the same amount of time doing aerobic activities, according to a new study by Harvard School of Public Health (HSPH) researchers and colleagues.

That does seem to support the attention-grabbing headline. But if you read further, you see this quote from the lead author of the study:

"Engaging in resistance training or, ideally, combining it with aerobic exercise could help older adults lessen abdominal fat while increasing or preserving muscle mass."

Hmm, so actually, it's best if you run and lift weights. That leads to the next question, which is, are runners more likely to lift weights too, or are lifters more likely to run too? I wouldn't purport to know the answer to this, but it would seem somewhat critical to anyone trying to draw a conclusion about which is "better," lifting or running.

Moreover, you don't have to look very far to see conflicting studies, like this one, whose abstract reads:

Aerobic exercise is your best bet when it comes to losing that dreaded belly fat, a new study finds. When Duke University Medical Center researchers conducted a head-to-head comparison of aerobic exercise, resistance training, and a combination of the two, they found aerobic exercise to be the most efficient and most effective way to lose the belly fat that's most damaging to your health.

What is one to make of all this? I'm neither a scientist nor a physical fitness trainer, but given human nature, I'd guess that the "best" exercise for any health benefits is the one that the person in question is most likely to stick with, preferably at an appropriate intensity level. If there were conclusive evidence that running was of only marginal health benefit while weightlifting was of significant value, I guess I would shift to lifting, but I don't think I'd like it. (Maybe I would grow to like it, but I doubt it.) Even now, I recognize that I would almost certainly be "fitter" if I shifted, say, 10% of my exercise time from running to other activities, but I like running and care about getting better as a runner. Hence, I get a lot more exercise than I would if I were limited to weightlifting.