I don't follow. How can consumption increase economic growth when it comes at the cost of investment? Investment is what creates economic output.
Economic activity, i.e. positive-sum trades, are what generate economic output (that and direct labour). Investment and consumption demand can both lead to economic activity. AIUI the available evidence is that with the current economy a marginal dollar will produce a greater increase in economic activity in consumption than in investment.
Haven't had one of these for awhile. This thread is for questions or comments that you've felt silly about not knowing/understanding. Let's try to exchange info that seems obvious, knowing that due to the illusion of transparency it really isn't so obvious!