If you are referring to causes of obesity, caloric excess is certainly part of the problem. I think the author is attempting to make the point that 'it's compli

If you are referring to causes of obesity, caloric excess is certainly part of the problem. I think the author is attempting to make the point that 'it's complicated'. I think the question the author raises is a good one. We don't have a very good handle on what bacteria live in our bodies, much less what they all do. If we are destroying certain bacteria with antibiotics inside us, what does that mean for our bodies? There appears to be a long observed correlation between ingesting antibiotics and weight gain.