Human
In general, humans can survive for two to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days. About 36 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the global burden of disease. However global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed, and a few developing countries. Worldwide over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
Addax
The addax are amply suited to live in the deep desert under extreme conditions. They can survive without free water almost indefinitely, because they get moisture from their food and dew that condenses on plants. Scientists believe the addax has a special lining in its stomach that stores water in pouches to use in times of dehydration. They also produce highly concentrated urine to conserve water. Pale colour of the coat reflects radiant heat, and the length and density of the coat helps in thermoregulation. In the day the addax huddle together in shaded areas, and in cool nights rest in sand hollows. These practices help in dissipation of body heat and saving water by cooling the body through evaporation.