Earlier quoted context omitted.
Yeah how lean you are is more diet. I meant that getting leaner through some combination of diet and exercise will make those goals all more achievable, which has obvious health benefits and is something I had in mind when deciding on those goals.
You'd also be surprised at how little evidence there is that diet is an effective long term weight loss strategy.
Studies that rely on self-reporting eating history skew the results to ambiguity, but studies in which the experimenters have full and unambiguous knowledge of calories and macronutrients consumed by subjects reveal that the difference in calories digested and the calories burned explains pretty much all changes in weight. It gets only slightly more complicated when talking about body composition (basically, eat enough protein to support your lean body mass and any athletic activity), and even more complicated when talking about long term health (e.g., micronutrient levels that support long-term physiological maintenance mechanisms which are neglected in the sub-clinical nutrient deficient states most people find themselves in).
Fairly simple linear relationships can be used to freely manipulate one's weight, as shown by pretty much any bodybuilder or athlete competing in a sport with weight classes.
Studies aside, it's obvious that relationship between calories digested compared to calories burned is the main determinant of weight as starving populations around the world can tell you. You can't create or maintain mass without the required energy to support cellular metabolism. The physiology and biochemistry is understood well enough for this not to be an issue. The problems professed by the media reporting on studies are mainly ones of measurement (as people don't usually know how to accurately measure their caloric intake, which is why self-reporting studies are basically worthless) and commitment to lifestyles in which they don't chronically overeat relative to their activity level.