Review by the National Health Service (NHS) of the publication "Physical activity energy expenditure has not declined since the 1980s and matches energy expenditures of wild mammals"in the International Journal of Obesity:
The researchers collected a number of experimental studies, which all used a sophisticated technique that indirectly measures an individual’s energy demands throughout the day. They found that when energy expenditure is measured in this way, the results show that people are no less active than they were 20 years ago.
Although this study found no evidence of a decline in energy expenditure, it's possible that other more direct measures of physical activity in more representative groups of people could find an association. On its own, this study doesn’t overturn conventional wisdom that changes in energy intake and physical activity both have a part to play in the emerging obesity epidemic.
