Summary
- A single meal can decrease the risk of hypothermia during a few km travel in severe cold. Consequently, it could also decrease the risk of frostbite, but lack of studies prevents making any reliable conclusions.
- Dietary protein generates more heat than carbohydrates and these more than fat.
- Proper hydration can contribute to prevention of frostbite, because dehydration results in constriction of blood vessels in the skin.
- In cold environments alcohol may lower body core temperature.
Macronutrients
After eating, some energy from food will be released as heat. This is known as diet-induced thermogenesis. The percent of calories that is converted to heat:
- 15-30% from protein
- 5-10% from carbohydrates
- 1-3% from fat
- ~10% from a mixed meal
According to Nutritional Needs in Cold and High-Altitude Environments: Applications for Military Personnel in Field Operations (National Academic Press, 1996):
- Fat has the lowest thermogenic effect.
- Carbohydrates have higher thermogenic effect, which can last for 2-3 hours and protein has even higher effect that can last 5-6 hours.
They also say:
A protein snack prior to retiring to sleep could provide some benefit
from the thermic effect of protein in cold environments.
and:
The principal mechanism to reduce heat loss is the neurologically
induced constriction of vessels in the skin and extremities. This
response diminishes heat transfer from the body core to the surfaces.
As a result, body surface temperatures fall rapidly upon exposure to
cold (Veicsteinas et al., 1982). These low skin and extremity
temperatures can result in cold injuries, especially to the hands and
fingers.
..which means that hypothermia increases the risk of frostbite.
In one small 2002 study, they measured the effect of high-carbohydrate and high-protein meal on heat production:
Postprandial thermogenesis at 2.5 hours post-meal averaged about
twofold higher on the high protein diet versus the high carbohydrate
diet.
In another small 1999 study, they have found similar results:
A high protein and carbohydrate diet induces a greater thermic
response in healthy individuals when compared to a high fat diet.
Water
Dehydration can cause constriction of blood vessels in the skin and can thus increase the risk of frostbite. According to one 1998 study, dehydration can reduce the blood flow through the skin in an exercising person by ~40%. So, proper hydration can contribute to prevention of frostbite.
