Why does cold weather decrease appetite?

Cold Weather and Appetite Suppression

Contrary to popular belief, cold weather does not consistently decrease appetite in humans—in fact, cold exposure typically increases energy expenditure without suppressing hunger or reducing food intake. 1

Metabolic Response to Cold

Cold exposure activates thermogenic mechanisms that increase energy expenditure:

• Cold environments increase metabolic rate by approximately 30% above basal levels when ambient temperatures drop below the thermoneutral zone (28-32°C). 2
• Short-term mild cold exposure (18°C for 2.5 hours) increases resting energy expenditure by 7-11.5% without affecting hunger sensations or actual food intake. 1, 3
• The body responds to cold through both shivering thermogenesis (skeletal muscle) and non-shivering thermogenesis (brown adipose tissue activation). 2, 4

Appetite and Food Intake in Cold

The evidence consistently shows that cold exposure does not suppress appetite:

• No differences in hunger scores, food intake, or satiety occur after mild cold exposure compared to thermoneutral conditions. 1
• In individuals with obesity, 90 minutes of cold exposure (10°C) produced only minimal changes: energy intake increased 10% during the immediate post-exposure meal, then decreased slightly for the remainder of the day, with no net effect on daily energy balance. 5
• Cold exposure may alter food preferences (decreased reward value for high-fat foods) without changing total energy intake. 5

The Altitude Confusion

The misconception about cold and appetite likely stems from confusion with high-altitude effects:

• At elevations >1500 meters, appetite genuinely decreases and food preferences change, with increased carbohydrate consumption at the expense of fat and protein. 6
• This altitude-induced appetite suppression is a distinct physiological phenomenon unrelated to temperature. 6

Cold Weather and Energy Requirements

In cold environments, carbohydrate requirements actually increase rather than decrease:

• Athletes and active individuals require increased carbohydrate intake when performing in cold conditions to maintain performance. 6
• The body prioritizes maintaining core temperature, which demands additional energy substrate. 4

Seasonal Metabolic Adaptation

• The metabolic response to cold is 11.5% higher in winter compared to 7.0% in summer, indicating cold adaptation over time. 3
• This seasonal variation suggests the body becomes more metabolically active in colder months, potentially increasing rather than decreasing energy needs. 3

Clinical Implications

The thermal discomfort from cold exposure is significant and negatively correlates with thermogenesis:

• High cold sensation scores are associated with reduced thermogenic response, suggesting individual variability in cold tolerance. 1
• Thermal discomfort may indirectly affect eating patterns through behavioral changes (seeking warm foods, staying indoors) rather than through direct appetite suppression. 1

Important caveat: While cold itself doesn't suppress appetite, cold-related factors like reduced thirst perception can lead to dehydration, which may be misinterpreted as reduced appetite. 6 Cold environments stimulate diuresis and reduce thirst sensation, potentially affecting overall nutritional intake indirectly. 6