In the workplace, Lean is a term most often used in reference to a way of thinking and acting, a management philosophy and process, that maximizes value while reducing waste – usually, paying homage to the Toyota Production System (TPS). However, I’ve observed colleagues from many different organizations state that they lack the resources required to provide value because their organization “runs lean.” Fiscally conservative about adding cost, sure. Lean, no.
Being over-resourced is wasteful, but being under-resourced is often even more wasteful and damaging to creating value while eliminating waste. Each of the forms of waste and flow are negatively impacted by being inappropriately resourced. All the worse, it’s usually stated with a sense a pride, as if good stewardship is being practiced.
If Six Sigma is the management strategy of your organization, being under-resourced is at cross purpose with your goals too. The goal of six sigma is to improve quality through reducing process variability. Being under-resourced most often reduces quality and increases variability.
Lean is an investment strategy. Describing a system that is starved of a needed resource – human, material, or other – as Lean is inaccurate. This is a perversion of the fundamental ideas of Lean and Stewardship.
Work Arts 
Yes, we hear this already: “we’re already lean” but that is just meant to say that we don’t have the resources we need. Lean is not about less as much as it is about more. I’ve never seen a company cut their way to prosperity. Lean is about more value, more capacity, more capability, more engagement.