Or is loosh just a darker lower frequency component as altered by our negative thoughts and feelings? If the latter, is that a byproduct of consciousness, an energetic parallel to the metabolic waste of the body produced by the processing of nutrients?

That is a useful analogy and is a good description of the true nature of loosh, that it is the darker end of the spectrum. The God-force energy is of a high vibration initially, that enters you. What you do with it will then begin to change it. Some things are utilized more than others, and that is a product of your state of being. The loftiest and highest of vibrations may not resonate for you if you are living a difficult life and struggling and have been beaten down by setbacks and hardship, so in a sense, is lost to you because it cannot fit in under the current circumstances. The more neutral, basic housekeeping energies can be embraced more readily and of course, are vital for your life maintenance. Beyond that, the processing of the energy to turn it into action has consequences, and ultimately, that divine life force can be lowered considerably in frequency. If there is much inner negativity that corrupts thinking and gives rise to dark thoughts and dark emotions, like anger and fear, that will take a toll on the person and creates a very negative and unsavory end product that is very much like waste excreted from the body. Not only is it being no longer of use, but an actual danger should it build up within at too high a concentration. It must be gotten rid of. The same is true of the products of consciousness that they can become toxic to the being. You see this in the phenomena involving the thought plane. It is also a kind of manna from heaven for the spirit meddlers. To have this dark loosh energy in abundance in a person who struggles and is unhappy, and so on, they become a perfect victim being a great source of the most useful and desired energetic frequencies by the spirit meddlers. It is like the flies buzzing around feces. The nature of their existence is, they get the leavings.