Human illnesses can be understood as damage to those adaptations that we took on at various stages in our evolution from pre-life molecules to modern Homo sapiens. Preventing these illnesses entails avoiding what causes the damage-- which too frequently are the everyday hazards of twenty-first-century life, as the chart below shows:

Level of Evolution

Cause of adaptive failure

resulting disease or problem

Pre-life

Environmental poisons

Certain birth defects

Single cell (bacteria and amoeba-like)

Viral infection

Colds/flu/HIV

Morula (sponge-like)

Cellular stress

Cancer

Chordate

Physical stress

Back pain

Fish

Excess dietary salt

Hypertension/heart disease

Amphibian

Tobacco smoke

Lung cancer/emphysema

Lower primate

Excess dietary sugar

Diabetes mellitus

Higher primate

Vitamin C deficiency

Scurvy

Ape

Excess dietary protein

Gout

Homo sapiens

Reduced dietary variety

Nutritionaldiseases/food allergies