Human beings are natural energy generators, and it is this which allows us to construct buildings and create art. So exactly what is human energy harvesting, and why should we be bothered with it? Furthermore, how does munching away on that bag of potato chips help?
Introduction
The human body is a natural energy generator. 
From chemical and thermal processes produced from our eating, kinetic energy produced from our movements, electrical activity produced from our brain, biomass waste produced from our bodies, and fluid flow engendered by our respiration, we are prolific energy producing factories.
Energy harvesting uses natural processes such as wind and tidal waves to capture and store energy. This energy is transformed into a different form, such as electricity, to power devices. The goal of human energy harvesting is the same. Human beings store energy in various ways, and one of them is in the fat you produce when you nosh on your favorite cookies, for example.
Why Human Energy Harvesting?
The idea of using human motion to produce electricity is not new. Hand-cranks power radios, blenders, ipods, and many other electrical devices. In the search for "clean" sources of energy, scientists and engineers are now studying ways to make the process more ubiquitous and efficient. The stakes are huge, with projections in the range of billions of dollars.
Also, humans make good power sources. The energy would be basically always available, has a small thermal footprint, and does not require any special fuel. Using human energy that would normally go to waste would be an ultimate achievement in recycling.
How Noshing Helps The Cause
The average human who has 15% body fat can produce 11 kilowatt hours of energy. 
The average human also eats about 3.3 kilowatt hours per day. The first law of thermodynamics prevents total energy capture, but you are of interest for harvesting because you have available approximately 128 watts when you stand, 163 watts when you walk normally, and 407 watts when you walk quickly. If you are a sprinter, over 1.6 kilowatts is available, and if you are a long distance runner, you have about 1 kilowatt available. Being asleep you are still useful; then you contribute 81 watts of power.
Of course the available energy production varies according to age, weight, metabolism, gender, and health.
Now that we know what human energy harvesting is, and how eating helps, what specific contributions from our bodies are researchers interested in? For example, we know that walking and standing helps, but what about sitting, or even energy output from our internal organs? We will look answer these questions in part two.
References
Image Credits
Pirate by Oakland
Hand-cranked phone charger by Virgin Media
Eating by Singhajaykr25
Resources
An Introduction to Human Energy Harvesting
In this series, we learn about the basics of human energy harvesting. We discover what it is, the specific human activities that are useful for energy conversion, and discuss the current research being undertaken to make human energy harvesting devices available for popular consumption.