Do you feel colder on an empty stomach? Here's why.

December 30, 2025 •

4 min read

Research has consistently shown that calorie restriction can lead to a drop in core body temperature, which is a key reason you might feel colder on an empty stomach. This sensation is a complex physiological response rooted in the body's innate need for energy conservation when fuel is scarce.

Quick Summary

When hungry, your body conserves energy by slowing its metabolic rate and prioritizing vital functions over heat generation. Low blood sugar, reduced insulation, and hormonal changes all contribute to the sensation of coldness.

Key Points

Metabolic Slowdown: An empty stomach triggers a reduced metabolic rate to conserve energy, resulting in less heat production.
Low Blood Sugar: Hypoglycemia from lack of food can cause shivering and cold sensations as the body lacks fuel.
Fat as Insulation: Less body fat, often from weight loss or being underweight, provides less natural insulation.
Hypothalamus Control: The brain's hypothalamus, which regulates both hunger and temperature, shifts focus during hunger to conserve resources.
Hormonal Shift: Hunger triggers hormonal changes, such as increased cortisol, which can influence body temperature perception.
Nutrient Intake: Consistent meals with a balance of macronutrients help maintain stable blood sugar and energy levels.

The Science Behind Your Chills: Why Hunger Makes You Cold

Feeling chilly when your stomach is empty is a common experience, not just a figment of your imagination. The primary reason is your body's highly efficient and complex thermoregulation system. When it senses a lack of incoming fuel, it initiates survival-oriented changes to conserve energy, and regulating your core temperature is a significant part of this process. This adaptive response is the root cause of the cold sensation.

Your Body's Metabolic Slowdown

Your basal metabolic rate (BMR) represents the energy your body expends on fundamental life-sustaining functions while at rest, including maintaining body temperature. Digesting food actually contributes to your BMR via the thermic effect of food, which generates heat as a byproduct. When you don't eat, your body slows down its metabolism in a process called adaptive thermogenesis to conserve energy. This is an evolutionary survival mechanism designed to help you endure periods of famine. With a slower metabolism, less heat is generated, leaving you feeling colder.

The Role of Hypoglycemia (Low Blood Sugar)

Blood glucose is your body's primary and most readily available source of energy. A drop in blood sugar, or hypoglycemia, is a well-known side effect of not eating. When blood sugar levels fall, the body triggers various counter-regulatory measures. One such response is shivering, an involuntary muscle contraction that generates heat to warm the body. While shivering is an obvious sign, a more subtle cold sensation can occur even before it starts, especially in individuals with blood sugar regulation issues like diabetes.

Hormonal Responses to Hunger

Your endocrine system plays a critical role in managing both appetite and temperature. The hypothalamus, a region in the brain, is the central hub for regulating both hunger and body temperature. During periods of hunger or calorie restriction, hormonal signals change. Levels of cortisol, the "stress hormone," can increase, which impacts how your body perceives and regulates temperature. Furthermore, thyroid hormones, which regulate metabolic rate, may be suppressed in long-term calorie deficits, further contributing to a slower metabolism and increased cold sensitivity.

Comparison: Fed vs. Empty Stomach


Feature	Fed State	Empty Stomach State
Metabolic Rate	Elevated, especially during digestion due to the thermic effect of food.	Reduced (Adaptive Thermogenesis) to conserve energy when fuel is scarce.
Blood Sugar	Stable and well-supplied, providing fuel for all bodily processes.	Potential for hypoglycemia (low blood sugar), triggering shivering and cold feelings.
Hormonal Signals	Regular release of satiety hormones like leptin, and lower levels of stress hormones.	Increased release of hunger hormones (ghrelin) and stress hormones (cortisol).
Heat Generation	Active, consistent heat production from metabolic processes.	Decreased, as the body conserves energy by lowering heat output.
Insulation	Body fat provides insulation, but muscle mass is also a factor in heat generation.	In underweight individuals, less fat and muscle mean reduced insulation and heat production.

Combatting the Cold: Simple Tips and Nutritional Support

If you frequently feel cold on an empty stomach, addressing your nutritional habits can help. By providing your body with regular, consistent energy, you can prevent the triggers that lead to metabolic slowdown.

Strategies to Stay Warm and Energized

Eat Regular Meals: Consistent meals throughout the day help maintain stable blood sugar and energy levels, preventing the body from entering a conservation mode.
Choose Complex Carbohydrates: Opt for whole grains and root vegetables, which take longer to digest and provide sustained energy, helping to maintain warmth.
Include Healthy Fats: Fats are calorie-dense and essential for overall health. Incorporating nuts, seeds, and avocados can provide sustained energy.
Prioritize Protein: Protein intake is crucial for muscle mass, which generates heat. Ensure your meals include a good source of protein, like lean meat, beans, or eggs.
Stay Hydrated: Dehydration can affect thermoregulation. Drinking plenty of water or warm beverages like herbal tea can help regulate your temperature.
Don't Fear Warm Drinks: A hot cup of tea or a bowl of soup can provide immediate comfort and warmth while you wait for your next meal.

Conclusion

While a chilly sensation on an empty stomach is a normal and protective biological response, it's a clear signal from your body that it needs fuel. Consistent, balanced eating and proper hydration are the most effective ways to avoid the metabolic slowdown and low blood sugar that trigger this feeling. If persistent coldness is an issue, it's worth speaking with a healthcare professional, as underlying conditions like anemia or a thyroid disorder could also be factors. Taking proactive steps to regulate your food intake can help you feel warmer and more energized throughout your day.

For more in-depth information on the physiological responses to starvation, the National Institutes of Health (NIH) provides extensive research on subjects like adaptive thermogenesis and hormonal changes during calorie deficits: https://pmc.ncbi.nlm.nih.gov/articles/PMC3943438/

Frequently Asked Questions

You feel colder because your body lowers its metabolic rate to conserve energy when fuel is scarce. Low blood sugar (hypoglycemia) can also trigger shivering and a cold sensation as a survival mechanism.

Yes, skipping meals can cause a drop in your blood sugar levels. In response, your body slows down its metabolism to conserve energy, leading to a noticeable feeling of coldness.

While temporary coldness from hunger is normal, persistent coldness could be a symptom of underlying issues like anemia or a thyroid condition. It is best to consult a healthcare provider for a proper diagnosis.

Yes, your body enters a state of adaptive thermogenesis when it senses a prolonged calorie deficit. It reduces your resting metabolic rate to conserve energy, making you feel colder and making weight loss more challenging.

Eating balanced meals that include complex carbohydrates, healthy fats, and protein provides sustained energy. Warm beverages and soups can also offer immediate warmth.

Yes, if you have a low body mass index or have lost significant weight, you have less body fat to serve as natural insulation. This can make you more sensitive to cold temperatures.

The hypothalamus, a region in the brain, is responsible for regulating both hunger and body temperature. When you are hungry, it can prioritize other essential functions, which results in a feeling of coldness.