Understanding the energy expenditure required for the activities of daily living is a critical step in assessing the caloric needs both of those individuals whose body mass exceeds recommended standards and those who are chronically under/malnourished. Knowing how much energy people require to accomplish their activities of daily living, which typically includes walking with burdens (carrying excess weight) and on sloped surfaces, is a critical component in developing guidelines for appropriate caloric intake. Activity energy expenditure is the second largest component of daily energy use, after the energy required to maintain bodily function (usually called resting metabolic rate (RMR)). This study allows us to understand the relationship between burden, gradient and walking which is necessary to accurately account for the daily caloric needs of humans. To evaluate this relationship, data is collected from a large number of female participants. Participants walk at three self-selected velocities (slow, normal, and fast), on five gradients (flat, slight uphill and downhill at a gradient of (6.7%), and steep uphill and downhill at a gradient of (12.6%)) and two burdens (no burden and a burden of a 10 kg backpack).“Self-selected” velocity means that the subjects are able to choose their own pace, be it slow, normal or fast. This approach allows flexibility for the subjects to choose speeds that reflect their normal routine. The energy consumption is measured by the volumetric rate of oxygen consumption (VO2, inspiration) and carbon dioxide (VCO2, expiration) with a portable Cosmed K4b2 device. Unlike previous work that has used treadmills, this study is completed outside in an urban setting. Preliminary results indicate that walking outside requires different energy expenditure than walking on a treadmill. This study provides data collected from real-world experience, thereby providing more accurate understanding of the caloric needs to achieve more day-to-day activities.