A new study published in the journal Physiology & Behavior has revealed that spending just half an hour submerged in cold water can cause people to eat significantly more in the hours that follow—a finding with important implications for fitness enthusiasts, athletes, and those pursuing wellness routines involving cold-water therapy. As cold-water immersion grows increasingly popular in Thailand and worldwide, especially for its touted benefits in muscle recovery and mood enhancement, this latest discovery raises new questions about its impact on eating behavior and weight management (PsyPost).
Researchers in the United Kingdom designed the experiment to isolate the effect of passive cold-water immersion—meaning no prior exercise, just sitting in cold water. The small but well-controlled trial recruited 15 healthy, physically active adults aged 20 to 59, all of whom completed three different trial conditions in random order. In one session, participants were immersed chest-deep in cold water at 16°C (about 61°F) for 30 minutes, while in the other two sessions, they either sat in warm water (35°C, or 95°F) or simply sat in a room with air at a thermoneutral temperature (26°C, or 79°F). All procedures were conducted at the same time of day, and participants followed identical pre-trial routines, including a standardized breakfast.
The core finding was striking: individuals ate about 34% more food after the cold-water session than they did after being immersed in warm water, and 32% more than after the comfortable room temperature condition. On average, participants consumed 2,783 kilojoules (kJ) following the cold-water immersion, compared to 1,817 kJ and 1,894 kJ in the warm water and air conditions, respectively. This suggests that the act of shivering and internal cooling triggered by cold-water immersion may provoke a physiological response—one that drives increased food consumption even when people don’t consciously feel hungrier.
The implications of these findings resonate strongly in the Thai context. In recent years, cold plunge pools and cryotherapy have gained traction in Bangkok’s rapidly expanding wellness industry, with urban spas and fitness centers promoting cold-water treatments for muscle recovery, reduced inflammation, and even mood improvements. Many amateur athletes and everyday fitness enthusiasts in Thailand now turn to cold-water baths after intense exercise or as part of general health regimens, unaware of the possible effects on their appetite and calorie intake.
One key detail from the study is that, despite consuming much more food after cold exposure, participants did not report feeling any hungrier than in the other conditions. Nor did their sense of fullness or satisfaction vary, indicating that the increase in eating was likely triggered by subconscious physiological mechanisms rather than psychological cravings. “While participants did not endorse greater hunger or reduced fullness, their intake increased after cold-water immersion—suggesting a physiological drive to restore thermal balance through calorie intake,” the study authors noted (PsyPost).
The researchers also measured core body temperature, shivering, heart rate, and energy expenditure throughout each session. During the cold-water immersion, energy expenditure was higher (around 224 kJ burned) than in either of the warmer conditions (135 kJ and 129 kJ, respectively), and most participants reported some level of shivering. Intriguingly, body temperature did not drop during the 30-minute cold-water session itself, but fell significantly during the 15 minutes afterward—a phenomenon known as the “after-drop,” when colder blood from the skin returns to the body core after immersion.
This after-drop may be central to the observed effect. The researchers hypothesized that the body’s response to this delayed cooling is an increased drive to eat—possibly to generate heat through the thermic effect of food, where the energy cost of digesting food helps raise body temperature, restoring homeostasis.
There are practical implications for Thai readers who use cold-water immersion for recovery or health reasons. While the process does increase energy expenditure, the additional calories burned are relatively minor compared to the extra food people tend to consume afterward. Over time, this could undermine weight management efforts and lead to inadvertent weight gain if dietary intake isn’t carefully monitored.
International studies have long debated the metabolism-boosting properties of cold exposure. Animal research has shown that brain regions linked to hunger, such as the hypothalamus, are activated in the cold and foster food-seeking behavior. The new human study aligns with these findings—even without a conscious increase in hunger, the physiological response to cold may override subjective control of eating.
While its sample size is small (15 participants), the study was robustly designed and results were statistically significant regardless of age, gender, or body size. However, limitations remain: the study measured only short-term effects, did not track overall daily food intake, and did not assess hormone levels linked to appetite regulation (like ghrelin or leptin). More research is needed to see if Thai people—or those in other climates—might adjust their eating later in the day to offset the extra post-immersion calories, or if repeated cold exposure leads to body weight changes over months.
A senior researcher at a major Thai university’s faculty of sports science, who was not involved in the study, commented: “While cold-water immersion is widely used for muscle recovery among athletes in Thailand, this evidence suggests we need to be more attuned to nutritional strategies post-recovery. Guidance for athletes—both elite and recreational—might need updating to account for a possible increase in appetite not accompanied by an increase in perceived hunger.”
Some practitioners at Thai wellness centers also stress the importance of balancing cold therapy with mindful eating. A lead spa manager at a prominent Bangkok wellness center suggests, “Those incorporating regular cold plunges should work with nutritionists to monitor and customize their post-session meals. Traditional Thai diets, often celebrated for their fresh ingredients and balanced flavors, can be adapted to avoid extra calorie intake after cold-water therapy.”
From a broader cultural perspective, the intersection of temperature, environment, and eating behavior is not new to Thai society. Rural customs of turning to hearty, warming dishes during the short northern winter are rooted in traditional beliefs about food and climate. Yet, few were likely aware that exposure to cold—in water rather than air—could drive a hidden physiological urge to eat more, even when not hungry.
As Thailand’s wellness economy and fitness culture continue to modernize and adapt international trends, such research will be essential. Going forward, Thai professionals in health, sports science, and wellness should consider how environmental factors—be it heat, humidity, or cold—impact physical and nutritional health. The study’s authors note that future research should look at longer or repeated cold-water exposures, impacts on appetite-regulating hormones, and how factors like body composition or overall fitness influence susceptibility to this effect.
For now, the key recommendation for Thai readers is simple but vital: If using cold-water immersion as part of a health, fitness, or mood-boosting routine, be mindful of your eating afterward. Monitor food intake, and consider working with a nutrition professional to avoid accidentally overcompensating for the increased calorie burn with even greater calorie consumption.
In conclusion, while cold-water immersion offers well-documented benefits for muscle recovery and well-being, its influence on eating behavior represents a new variable that Thais using these therapies should not overlook. Sustainable health and fitness depend on a holistic awareness of how interventions affect the body—not just in isolation, but as part of an interconnected system. As cold-water baths become a mainstream part of Thailand’s wellness culture, understanding the hidden appetite trigger may help keep wellness goals on track.
For more information, see the full publication in Physiology & Behavior and reporting by PsyPost.