How does it matter where the calories are from?

I believe that protein is used by the muscles for growth and repair, while the rest is just stored by the body and not really used for any sort of repair or growth.

But I have no research to back up my statement.

I thought that when working out and lifting weights you actually are tearing the tiny muscle fibers which is where the protein comes into play. The protein is used to build and repair, which is why they say that you really only build on your rest days during the muscle repair.

Well carbs are burned before fat, which is why alot of people tout a "low carb diet". If there isn't any carbs to burn, you are going to burn fat.

But carbs give you energy, and are used for basically every move you make throughout the day, and if you are working out alot then you are burning the carbs off as well as the fat.

I just learned to day that Protein actually creates something like 0.4g of carbs for every 1g of Protein. So that may be worth something when you eat in surplus to gain muscle

But again, there are people on here that know more in their pinky finger than I will ever know....so hopefully someone else can weigh in.

I've followed on and off the diet principles of the Zone Diet from Dr. Barry Sears. You might research his take on the matter for an in-depth analysis (and there's a lot of that), but I'll try to summarize.

From a pure calories perspective, there is no difference. Once food macro-nutrients break down to glucose, (and even protein can be broken down to glucose, which is the idea behind Atkins), it's all the same. But that's for energy consumption by the cells for just about anything (breathing, exercise, thinking, etc.) and what is left over is stored as fat. Now, how much gets stored as fat can vary based on the insulin response from the glycemic load (GL) of the meal, which is also mitigated by the current activity level.

High glycemic loads stimulate a high insulin response, and if you don't actively need all that glucose (in the case, for example, of a high-carb, high GL meal, like pasta and bread with limited meat/protein and low-fat gravy), then it will get stored as fat (and quickly!). Some of the excess glucose will get converted to glycogen and stored in muscles, though unless you are generally active, will mostly be unavailable as a refuge.

Research shows that If the GL of a meal is lowered through judicious choices of the 3 macro-nutrients (Carbs, Proteins, Fats) into a ratio that limits the insulin response, then glucose will be able to float around in the blood for a while longer (because the insulin isn't high enough to force it into fat cells) and with glucose lowered, its counter-hormone, glucagon is around in sufficient quantity to allow fat cells to release their glycerins for conversion to glucose more readily when blood sugar drops.

In a nutshell, if you're going to be aerobically training non-stop (except to eat, I suppose), then you could consume anything that doesn't have a direct caustic effect on the digestive tract. But almost no one lives that way, so to better deal with the periods between meals (4-5 hours, roughly, with bridging snacks if necessary), a balanced diet of good-quality foods using a guideline of 40% carbs, 30% protein, and 30% (your ratio could vary slightly depending on how your body responds to carbs) will give you the best energy nutrition profile with regard to fueling your body for daily activity, including exercise.

Now to finally answer your question on consuming calories to build muscle, you need adequate protein to rebuild from the intentional injury caused by weight training. The ratio for heavy training, like elite athletes, is 1g of protein/lb of lean mass (could be higher for super-intense regimens). So a hypothetical 167 lb. man (at 10% body fat) wanting to add 10 lb. of lean mass, he would need to safely consume extra calories that support his activity level. I suspect 4500 calories or 2800 excess calories is probably too much (and I realize it was only an example) unless he's working out 6 hours a day.

Here's the math. 150g of protein per day = 150 x 4 or 600 calories. Another 600 calories from fat and add in a 4/3 ratio 800 calories from carbs. That's 2000 calories. Now add in say 2 hours of working out a day. That's about 500 calories an hour for resistance training, so make it 3000 calories (comprising 1200 from carbs and 900 each for protein and fat). If this man isn't working out and eats at that level, he'll gain weight as fat about a pound every 2 days (assuming a sedentary workplace). If he is working out, then he has sufficient protein to fuel growth. Whether his muscles have the genetic capacity to grow (without the aid of steroids) is another matter, but they will be strong and well-repaired.

Incidentally, if lean weight doesn't increase at the 1g/lb ratio, increase it in steps of 0.1 until either it does or fat increases, which for the latter, probably betrays the alluded genetic limits.

Oh boy, what an extensive question...

Let me start by saying that a calorie is a calorie - it is simply a measure of the amount of energy it takes to warm 1 g of water by 1 degree Celcius (in a specific temperature). As a measurement, it is absolute... such as 1 metre is 1 metre is 1 metre.

However, where that calorie comes from is a different issue. 400 calories from Doritos is not the same for the body as 400 calories from a meal of chicken breast and veggies.

All energy the body uses are derived from converting 3 substances into glucose (simple sugar). Glucose is the only kind of "fuel" the body can use effectively (in addition to ketones, but that's beside the point for this question). The "stuff" all food is made out of are carbohydrates (sugars: simple or complex), protein (amino acids) and lipids (fatty acids).

Fats, carbohydrates and proteins are converted to usable energy by the body via different metabolic pathways. The conversions do not only yield energy, but also consume it. The body is extremely efficient in using nutrients for energy production, and it prioritises by using the easiest to use sources first... These are carbodyhydrates. If there are enough carbs in the diet to account for the energy needs of the body, the energy yielded from the other sources will be stored first as glycogen, then as fats.

The fact that converting carbohydrates to glucose is the least "costly" conversion is the reason behind the belief that low carb diets are efficient... If carb intake is low, fats and proteins are used for energy at a higher energy cost leading to a lower net energy yield from food sources... Doesn't quite work like that, but makes kind of sense.

This is not all there is to it, though. Glucose can only be used as fuel with the help of a hormone called insulin. Insulin allows cells to take up glucose from the blood to be used as energy (eventually converting sugars to Adenosine triphosphate, ATP). That is why if you have a diet of simple carbohydrates that are easily and quickly converted to glucose, your insulin level will quickly increase in reaction to the glucose influx. As a result, the glucose is then quickly used by cells, and the blood glucose level quickly falls... In other words, you have a sugar high, and drop quickly after it hungry again, or fatigued.

By eating a balanced diet, the glucose uptake from digestion is sustained over a longer period, insulin level in blood remains elevated, but normal for a longer time, and the food sustains you for longer.

So... It DOES matter where the calories come from, while at the same time a calorie is a calorie.


Phew... hope that makes some sense.

M

like nice explanation with substance and that makes sense.

You can't make muscle out of fat.

Thanks for the answer. So if we eat carbs we tend to put on more weight because we are hungrier sooner (tend to eat more) and it takes less calories to burn off.

No not at all, in fact, it's the opposite that happens
When you put yourself in an active lifestyle, you without really noticing that you are constantly burning more and more, there is a virtual circle in the process, the more you exercice, the more you eat, but the more you burn, and the more you put on lean mas, meaning an increased ability to burn (metabolism increases)
So the more you eat, the more you burn (you know how much I eat white and how lean I am)

So our “experiement” man would gain a little more weight because his body is burning less calories

More, always more that is what people don't really get, the less they eat while they train, the more their metabolism is efficient, you burn less because you eat less, and because you train more.

to utilise the calories he’s consumed from carbs and he would be hungrier because his blood sugar will drop quicker. Obviously he will consume less vitamins and minerals from his food by eating junk which might have a little effect on his appearance and performance.

Micronutrients are as important as macronutrients, but they don't provide energy, they enhance the whole mechanic
You def. won't find any vitamins into "junk food" - simply because processed food requires transformations that simply destroys all vitamins and minerals (as bad ways of cooking does at home)

As for insuline, while the glycemic index doesn't play a role in weight gain, it is true that high glycemic index food, after the glucose levels drop, people simply eat to speed up the process or glucose level restoration, but glucagon itself is able to do - takes a little more time , no more.
That's why low-glycemic index food are good for, they simply prevent the insuline yoyo (sugar brings sugar)

But it seems that other than fine tuning it won’t make much of a difference?

Macro affect the body composition - a distant runner doesn't have the same macros as an athlete, and you visually see the difference, but see it the other way - the activity defines the overall shape - the intakes maintain it (and the performances of couse)

Don’t get me wrong, I am all for healthy eating and getting the right food to fuel the body. I just want to know HOW important it is. I think many times people follow a certain diet without understanding it completely, and I am one of those people that can only get motivated by knowing the exact theory.
Thanks guys.

.... in conclusion, my moto is : train big/ eat big

that is also why I'm constantly pushing you - carbs don't make you gain weight, neither dietary fat. When you don't train, the food you eat on the same day will be used partially the same day (after the digestion) but also the next day, see it as a "cycle" - not eating when you don't train is a HUGE mistake, because when you don't train, the body is still a furnace (for instance, 30% of the ingested carbs are used by... the brain)