As a continuation of my previous post, I want to touch upon the topic of how much to eat with respect to carbohydrates. Hopefully, you understood which food items have good carbohydrates, and that solves the question about quality. What about quantity? In this post, I want to cover the quantity of carbs that one should eat. Remember that when it comes to food, quantity is as important as quality. Just because you are eating healthy carbs does not mean you can eat any amount. Well, actually if you are eating quality food, you will not be able to eat a lot of it really.
Disclaimer: I am neither a nutritionist or a fitness adviser. I don’t have any certification. Take all my advice with a pinch of salt. I have been into health and fitness since 2008 and that is probably my only credibility. I am not liable for any health issues that might arise following my advice. Risk is all yours.
Lets understand calories first. The reason we need food especially the body's preferred source of food -- carbs, is for energy. If your body is alive and you are able to do all the things on a daily basis, whether physically or mentally, is because your body is burning carbs to generate energy. The resting metabolic rate of a healthy adult is about 1300 calories. That is the minimum amount of energy we need everyday. And since we are not going to just rest all day, we need a few more calories than that. Most people agree on 2000 calories of energy requirement per day. But it varies quite a bit. If you are lean and short, you probably need much fewer calories than that. Likewise, if you are involved in some vigorous activity such as playing sports, then you might need more. So your body should be generating as many calories per day.
Now, how much energy does one gram of carbohydrate have? A gram of carbohydrate can provide 4 calories of energy. If we assume a 2000 calorie requirement, how many grams of carbs do we need per day? If you said 2000 / 4 = 500 grams of carbs, then you would be wrong :). Remember, we also need the other two macronutrients (fats and proteins) in the right proportions. Normally 50% of the calories should come from carbohydrates (and the proportion changes by body type as well, but that is a topic for another day). So given this information, the number of grams of carbs we need per day is about 250 grams. So if you eat 250 grams of good quality carbs, we should be done right? Nope, and so we need to understand calorie density and absorption rate.
Now you know both the quality and quantity of carbs you need. How you choose to get the calories from carbs now entirely depends on you. You could eat 250 grams of white sugar, which is about the amount a cake recipe would require you to add. Or you could eat 1.8 kilograms of apples (about 10 medium size apples), or 2.4 kilograms of carrots (about 40 medium sized ones). Choice is yours. Remember how I said that it is unlikely that you can eat too much of good quality food?
How did I arrive at those numbers anyway and why do we need to eat 2400 grams of carrots as opposed to just 250 grams of sugar to reach the same amount of calories? Here, we need to understand the calorie density of food. Hundred grams of white sugar has 100 grams of carbohydrates, because it is calorie dense. However, 100 grams of carrots has only 10 grams of carbohydrates. So you need to eat 2000 grams of carrots to equal just 100 grams of sugar. That is the difference in quantity. So it is easy to pack calories with just a few bites of cake or doughnuts, but you need to eat a lot of vegetables to get the required calories and your stomach will get full before your calories limit has reached. So, always eat quality food and quantity will take care of itself.
The other problem with simple sugars is that the body absorbs it very quickly. If all of the sugar cannot be used at the time of digestion, it gets stored as fat, because you cannot have too much sugar in the blood. The body's natural mechanism to reduce sugar in blood is to produce insulin which helps body store glucose in the liver. But if there is more sugar in the blood than what can be stored, then the body converts sugar into fat which gets stored in cells. So when you eat a lot of simple sugars, your body quickly removes the sugar, stores it as fat and then because the blood is out of sugar, you crave to eat more.
Instead if you eat food that digests slowly and unlocks sugar slowly, like when eating broccoli or oats, the sugar enters the bloodstream gradually and hence there is no spike of sugar in blood. No spike in blood sugar means no need for excess insulin and no need to urgently store the sugar as fat because your brain and other cells keep using the slow generating sugar. You won't feel hungry for a long time as well because the food is digesting slowly.
Don't get me wrong, there is a time for simple sugars, which is after your liver is depleted of its glucose. This could be due to some vigorous sports activity or weight training. Then you can have a small amount of fast digesting sugar, the amount that can be stored in the liver, which is usually around 300 calories. So no more than 75 grams of sugar (actually you need much less than that because your liver is never completely depleted). Although, even in this case I would only suggest a slow digesting healthy meal.
If you thought that was the end of carbs, you are wrong. There is more to come. But for now, to summarize we learned that
- the quantity of carbs is as important as quality
- one gram of carbs has 4 calories
- a gram of food does not always mean one gram of carbs because it all depends on the density of calories
- cakes are calories dense while most vegetables are not
- fast digesting carbs (such as white sugar, flour etc), cause body to store excess calories as fat quite quickly, where as slow digesting carbs reduce the chance of fat built up
Since we touched upon absorption rate, I want to talk about dietary fiber, glycemic index and glycemic load in my next post. Until then, eat healthy :).