The O2shape program combines the use of a protein-based smoothie with an uphill walking routine. This increases oxygen (O2) uptake from the lungs, as well as muscular capacity.
The smoothie increase the feeling of fullness, thus reducing total daily calorie intake. It also increase the effects of exercise with 25%.
The research referred to is published in major medical journals and can be found by searching for "Hoff and Helgerud" on PubMed.gov - the major database for peer-reviewed medical research.