When we need energy, can’t the body just burn the stored fat? Isn’t that the whole point of stored fat? Why will we feel hungry, weak, lightheaded, etc. at all? I understand if the body doesn’t have enough fat (if you’re super skinny), it would make sense to feel hungry, but I don’t understand why would that be the case if there’s enough fat to go around.
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The human body needs more than fat to survive. When you are hungry and need energy, you need vitamins, you need protein, you need fiber, you need all of these things that the body does not have the ability to store. We can only store excess calories as fat, but calories can come from anything, like pure sugar for example. For if you just ate pure sugar you would die.
I’ve fasted before and didn’t experience any of these symptoms except hunger. Some may be psychosomatic or leaned behaviors or your imagination. But whatever the case these experiences largely disappear after a few days without food . We are overfed and eat a lot of highly processed food too so sometimes we are artificially driving sugar levels up and down which can make you feel sick.
Also our bodies strive for balance. If you don’t eat food regularly you are not just missing calories , you are missing out on vitamins and minerals. You can adjust to much lower amounts of calories but you must still eat a certain amount of salt and other minerals. So your brain is trying to motivate you to find food. That can be very powerful. There are receptors throughout your brain that respond to various changes in what you eat, and they can make you act more aggressively more irrationally., and can even make you more willing to take risks
This is the question I asked myself and it lead me to intermittent fasting, now I’ve lost 10 kgs.
When our insulin levels are constantly high, we are in this perpetual vicious cycle of hunger and weight gain. My simplified understanding: Insulin has an antagonist hormone, glucacon. It takes energy from our fat! But glucagon can’t work when insulin is high. Insulin is doing its best to protect us from high blood sugar and putting it into stores as fat. The thing is, we never get to use those stores when we just keep eating crap all the time, and our insulin stays elevated. This is very harmful in so many ways. Look for example videos by Dr Pradip Jamnadas. I love his enthusiastic style. I’m Finnish and somehow like his directness!
Others mention the lag in extracting energy from our fat.
But I want to raise another point, that , hunger, weakness, lightheadedness are not just due to lack of energy in the body. E.g. dehydration can cause lightheadedness
Weakness can be due to muscle fatigue or damage which can be due to things like lactic acid buildup, decrease in oxygen due to oxygen being used up, and muscle fibre damage.
We burn carbs as energy by default. We have about 2000kcal of carbs in store. It takes some time to switch from carbs to fat as energy source, and during that time you will feel like you are running out of energy. But if you push through that transition, it will get way easier.
I used to fast before. Longest fast I did was over 60 hours. The first 24 hours is when you feel hungry. Then it goes away, as your body switches over to burning fats, and it probably has tons of that available for energy. Towards the end of my fast I was feeling fine and felt like I could do it indefinitely.
Imagine your fire is dying and you need fuel for the fire, sugar and caffeine are like a flammable liquid, complex carbs protein and fat are like kindling and wood and your stored fat is like a wet log
Because your body is not used to burning fat given a steady supply of carbs in your diet.
Carbs are a fast source of fuel, fat is slower to burn.
Switch to a low-carb diet (keto or any other) and you will stop having these week/lightheaded episodes.
Imagine that you’re living your normal life eating regularly, buying groceries when you need them, etc. But you also have an emergency stash of canned food hidden in a wooden box somewhere.
Now suppose something happened one day like gricery store ran out of goods or your paycheck got delayed. You missed your regular resupply at the grocery store. But is one wierd day enough a reason to go and bust tgat emergency box open? Probably not. You’ll check if things change tomorrow, then you’ll finish anything edible and filling that’s still left in your fridge and only then will you go through the work of opening the reserve.
That’s how your body acts too.
Fat is meant by the body as a reserve for the times of disaster. Think of it as savings. You don’t touch your savings as long as there’s income, you keep going with income until a disaster prevents you and that’s when you resort to savings, sparingly. That’s why the body just keeps asking for food and you give it as long as it is available and the fat reserves are safe until there is a famine or a hard time, then they will be used.
One thing i haven’t seen mentioned yet is that certain hormones can make you feel hungry even when you’re not, because they’ve essentially been trained to do so. The release of ghrelin- essentially the hormone that’ll tell your brain it’s hungry- into your system can become regulated based on your eating schedule. If it becomes used to eating certain foods (especially sugar) at certain times, then ghrelin can get released when it’s expecting it.
This is what can lead to regular snacking. Your body can become used to the regular input of food, and ghrelin is released when it doesn’t receive it, reinforcing the cycle.
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