if calories equal energy why do we feel more lethargic on high calorie foods like kebabs, fast food, pizza etc rather than more energetic. And why do we feel more energetic on lighter goods like chicken and salads.
In: 20
Our body needs time and energy to digest food. Heavy food makes us want to rest, so our body could focus on digestion and have lots of energy later. Light food gets digested fast, so we get smaller “shot” of energy faster.
Lighter foods are easier to digest. So when you eat heavy foods, and with your named examples likely far too much food, your body diverts blood to your gut to deal with the food. This diverts blood away from brain and muscles making you lethargic.
Adrenaline does the opposite and shuts down your guts to save resources for muscles and brain. That’s why stressful situations can leave you not feeling hungry.
Calories is a measurement of raw energy essentially, it doesn’t factor in how our body is going to convert it. You can measure the “calories” in gasoline, but drinking it will give you no usable energy.
Unless you are literally starving your body does not lack energy. Eg if you weigh 140 lbs and have 10% body fat, that equates to two or three weeks worth of stored energy.
So eating is not normally needed as a way to get energy into the body for immediate use. But to extract the nutrients from food, the body diverts more blood towards the digestive system; while exercise would divert more blood towards towards the muscles. So, when you eat a large meal, the body would rather get the nutrients, so it signals you to not do anything strenuous.
Calories is the energy you get from the chemicals in food you burn. You get them from fats, proteins, sugars/carbohydrates, alcohol and probably some others. These all burn differently. All these are harder or easier to ‘take in’. Sugars are easiest to get into your blood and easiest to burn. That’s why kids go nuts on them. Carbohydrates are chains of sugars that need an extra step to get them into sugars. Fats are the hardest to burn and hardest to get into your blood. So while your body is digesting them it’s working hard to get them out of your digestive tract and stored in your body. Fats do have the highest calorie count/gram. So high calorie food is very often fatty food. While your body is spending energy on digesting them it doesn’t have much energy left for much else so you feel lethargic. Chicken is mostly protein. Salads (the greens) is mostly nothing, just water, fibers and very little sugar, fat and protein.
Your sensation of feeling energetic or lethargic isn’t related to what physicists call “energy.” There’s no reason to expect them to match up. It’s like how if you bought a kit to test for lead paint, you wouldn’t expect it to give positive results for a can of modern paint attached to a “slip lead” style leash.
[removed]
One thing people often underestimate or misunderstand is how much work is required for digestion.
Some people feel a “hot flash” after a large/heavy meal, part of that is due to how much work your body is doing.
Eating a salad is like taking a brisk walk around the block in the morning. Not much effort but it “energizes” your system.
Eating a gut stuffing meal is like doing sprints for a full hour. Highly exhausting.
Ever overeat in the evening, then your gut feels sore in the morning?
Energy to digest will make you want to rest. The more you digest, the more you feel like you want to rest.
This is where the body is directing blood. If it’s being used to digest, it’s not being used for regular activty. Which is also why people will throw up if they eat to much and have a hard enough work out.
Latest Answers