The difference is that the conclusion of a scientific study is part of a structure that includes axioms, method, assumptions, experimental design, recorded data, and references; all of which are part of the presentation and are accessible. If you decide to read only the conclusion and not go deeper into the study, then any judgement you make is necessarily faith-based (or anti-faith-based). But if you DO actually read more of the study and not just the conclusion, then you can do something that would be impossible in a religion-only context. You can think critically without being heretical.

Just saying that our energy level has a strong genetic component is not helpful unless we also know the mechanism of causation. Usually genetics are responsible for something only indirectly. For example, does the new discovery imply that particular food cravings are genetic? Certain foods, and food combinations, increase the metabolic rate and certain other foods decrease it. Are there genetically determined individual reactions to certain foods, like the way allergies are individual, which alter the body's response to other foods? Or maybe our metabolic rate is affected directly?

The guy you saw on TV definitely had a problem, but his problem might have been the food cravings themselves (i.e. a dependancy relationship) for foods that didn't exist until 8,000 B.C. (refined carbohydrates). Or he may have just been a naturally lazy person, which is a very different thing. These recent discoveries, about the genetic influence on our energy levels, don't help at all in answering these questions.