The study is interesting but hardly conclusive (15% for example is not at all a proven figure). It was a limited number of cats and limited in other ways but does provide some indication that increase eating during winter, if food is available. If you limit food in order to keep the cat from getting too fat you might want to vary the amount a bit based on the season.
Periods of peak and trough food intake coincided with peaks and troughs in both temperature and daylight length. In conclusion, average food intake in summer is approximately 15% less than food intake during the winter months, and is likely to be due to the effects of outside temperatures and differences in daylight length. This seasonal effect in food intake should be properly considered when estimating daily maintenance energy requirements in cats.
Food intake was greatest during the months of late autumn and winter (e.g. October to February).
In conclusion, a seasonal effect on voluntary food intake exists in domesticated cats, whereby food intake is greater in winter and less in summer. These changes in food intake are likely to be the result of changes in ambient temperature, daylight length, or both, and the fact that they do not cause bodyweight changes suggest that they occur in response to changes in energy requirements. The possible effect of climatic variation on voluntary food intake in pet cats should be considered in companion animals, and may mean that feeding strategies may need to be seasonally adjusted, to ensure that availability meets demand at different times of the year.