Two feet? Lol

The average human needs 2,000 kcal to stay alive (2.32 KWh).

Military Recommended Dietary Allowances (MRDA): The MRDA suggests a baseline of around 3600 calories per day for operational rations to meet the energy demands of military units (4.184 KWh).

So your average humanoid military combat suit/drone needs a 4 KWh pack which can be swapped out and recharged.