More interesting still, LPL levels in humans also rise and fall in tandem with the seasons. Researchers from the University of Colorado studied a group of 12 women and 6 men in both the summer and winter.
Summer was classed as May through August. Winter was classed as November through February. LPL activity in both muscle and fat increased during the winter, and dropped during the summer.
Winter also sees a change in the activity of several fat-burning and muscle-building hormones.
For example, cortisol levels reach a low point in the summer . Not only is cortisol associated with the storage of abdominal fat, it's also been linked to all kinds of health problems, including diabetes, heart disease and depression. Cortisol may also weaken your immune system, leaving you more susceptible to colds and flu.
Testosterone, a powerful hormone which helps you build muscle and lose fat, tends to peak in the summer and early autumn. It also reaches a low point in the winter and early spring.