In ancient times, the main problem was to get food. Nowadays the difficulty is to decide for or against some foodstuff. In industrialized countries, this abundance led to the fact that people eat differently from what they should. Traditional populations were subject to periods of feast and famine. Those with a metabolism which stored energy with high energetic efficiency had a survival advantage. This is called the 'thrifty' genotype hypothesis. With the secured supply of calories, coupled with a sedentary lifestyle, the thrifty genotype becomes disadvantageous, causing obesity. Industrialization or 'cola-colonization' also leads to a dramatic increase in obesity and non-insulin dependent diabetes mellitus in developing countries. The spread of fast food restaurants all over the world has changed modern nutrition fundamentally. Influence begins early in childhood. Advertising concentrates on the selling of image over substance. However, fast food contains high levels of fat, especially trans fatty acids. Higher consumption of trans fatty acids was associated with a higher incidence of and mortality from coronary heart disease.