If I consume equal amounts of (say) mango, one in frozen chunks, the other at room temperature, will I digest them at different speeds? That is, will they have a different impact on my blood sugar levels, thereby having weight-control implications or being readily available for energy?
Following from the same, will heating beverages affect absorption rate?
I cannot answer all but I will do what I can...
Drinking hot beverages doesn't aid in the digestion, but it increases your metabolism. I drink hot water in the AM to help 'induce' a 'flushing' of my excess before big races. Drinking water near room temperature allows the water and fluid to be absorbed into your body quicker and easier. Thus room temp. beverages would be ideal for racing/running and hot beverages would be better pre-workouts when you might want to increase your metabolism. Unsure about food.
I know the first two from high school. My XC coach used to read up on this topic and share with the team quite frequently.
The rate of digestion depends upon the surface area of the food particles, and yes, its temperature, with the ideal temperature for gastric emptying being on the warm side (~43°C), but not hot. Similarly, enzyme activity is at its greatest at around core body temperature (~37°C) or slightly higher (~42°C), depending on the enzyme. However, the mechanical action of chewing breaks the food down into progressively smaller pieces, vastly increasing its surface area, and consequently the rate of chemical reaction. And since the rate of temperature change is also associated with surface area, and exponentially with temperature difference, the act of chewing very quickly normalises food temperature with body temperature. The temperature of liquids similarly normalise rapidly. The temperature of liquids has been found to have either no effect, or otherwise a small effect on gastric emptying, when the temperature is particularly low (4°C). And thus for the aforementioned reasons, properly-chewed food should be expected to have a similarly insignificant effect on digestion time, absorption time, and hence efficiency.
Every food we eat are digested by specific enzymes that are highly sensitive to temperature. For example, proteins and fruits are digested differently - different enzymes, timing and parts of the digestive canal. Beside all these, fruits as well as other raw foods have their own natural enzymes to ease digestion. Now the truth is that cold or hot foods and beverages are not good for our body. Raw Fruits and vegetables are good at room temperature, but every other cooked or processed foods are best at warm temperature. A food sample at different temperature will not have a different impact on your blood sugar level, though a natural and processed food will impact your insuline differently. For example, your body knows the difference between a ripe raw plantain and a plantain chips.
