# How do calories cause weight gain?

by Squippel
Tags: calories, gain, weight
 P: 4 It may superficially sound like a stupid question with a simple answer, but let me explain in more depth. Calories are units of energy, as you probably know, and grams are the the weight of the food. So calories are not directly related to the weight of a food. Foods range in the amount of calories per gram. So the meat of my question is basically this: if you eat the same weight of food, but foods with higher calories why do you start gaining weight? How or why does the energy cause weight gain? This is a possible solution I can think of: the extra calories somehow end up retaining more weight of the food than the otherwise would if you had consumed lower calorie foods. As an extra thought experiment related to this, imagine a "super seed" of 3,000 calories but only a weight of 1 gram. How could calories cause weight gain then? Obviously this is impossible, but it's just a thought experiment to view an extreme form of the question. Thanks for anyone who replies!
 P: 15,294 Calories are a unit of energy, true, but kCal (kiloCalories) - which is what food is measured in - is the chemistry that contains usable energy in the form of chemical bonds in proteins, carbs, fats, etc. When the body absorbs food that is high in kCalories, it can use those nutrients to build muscle and tissue, increasing weight. If a body absorbs more nutrients than it needs, it has a way of storing them for later use. High kCalorie foods are more likely to be stored, resulting in fat deposition and thus weight gain. Low kCalorie, high mass foods (for example, fibre) are more readily passed out of the body, so they do not add to weight. In the case of your super seed: A 3000 calorie 1g seed might have the entire 1g retained (and no, not more than 1 g). It is all useful nutrients that the body incorporates. A 100 calorie 1g seed would have a small fraction of that 1g retained - only that which is useful fuel or micronutrients. It is probably mostly fibre.
 PF Patron P: 347 For the way excess calories are stored see / search : Triglyceride Synthesis
P: 4

## How do calories cause weight gain?

 Quote by morrobay For the way excess calories are stored see / search : Triglyceride Synthesis
I'm an engineering student and have only taken 2 chemistry classes. It's hard to follow all the terminology used to explain triglyceride synthesis.

 Quote by DaveC426913 Calories are a unit of energy, true, but kCal (kiloCalories) - which is what food is measured in - is the chemistry that contains usable energy in the form of chemical bonds in proteins, carbs, fats, etc. When the body absorbs food that is high in kCalories, it can use those nutrients to build muscle and tissue, increasing weight. If a body absorbs more nutrients than it needs, it has a way of storing them for later use. High kCalorie foods are more likely to be stored, resulting in fat deposition and thus weight gain. Low kCalorie, high mass foods (for example, fibre) are more readily passed out of the body, so they do not add to weight. In the case of your super seed: A 3000 calorie 1g seed might have the entire 1g retained (and no, not more than 1 g). It is all useful nutrients that the body incorporates. A 100 calorie 1g seed would have a small fraction of that 1g retained - only that which is useful fuel or micronutrients. It is probably mostly fibre.
I know this will sound a bit imprudent, but my question literally boils down to this: "If you eat the same weight of food, but higher calories, do you poop out less weight?"
 HW Helper P: 6,164 Almost all of your body weight is water. You need energy (carbs and fats) and a little building material (proteins) to build cells, but the cells mostly consist of water. So the weight of the food is not so relevant, it's mostly the amount of energy (calories) in it that dictate the weight gain. A typical method to avoid weight gain, is to eat food with lots of fiber in it. Fiber contains no nutrition at all and is simply expelled by the body again, although it does have a beneficial effect on your digestive systems.
PF Patron
P: 347
 Quote by Squippel I'm an engineering student and have only taken 2 chemistry classes. It's hard to follow all the terminology used to explain triglyceride synthesis.
Metabolic Pathways are a complex subject of Biochemistry

Triglycerides or lipids , stored fat, are esters that are formed from glycerol ( a 3 Carbon
alcohol and 3 long chain fatty acids . Both of which can be synthesized from carbohydrates

Do a google search for Ester bond formation.

Then look at : The formation of ester bonds in the synthesis of lipids.
P: 15,294
 Quote by Squippel I know this will sound a bit imprudent, but my question literally boils down to this: "If you eat the same weight of food, but higher calories, do you poop out less weight?"
Yes.

You body will incorporate more of the fuel-containing nutrients that are in the higher calorie food.

Bulky food that contains fewer calories has a higher amount of bulk that is essentially passed through.

That's is a very simplistic answer, but yes.

There are important caveats that can't be ignored. As Yanick I_Like_Serena points out for example, most of your body weight is water. And your diet will affect how much water you retain. Many "diets" that promise to lose 10 or 20 pounds in just a couple of weeks are simply diuretics that cause you to drop water ballast.

So you can see that it is quite possible (in theory) to gain and lose weight independent of the weight of the food you consume. (We take for granted the water we consume, since it has no calories, no nutritive value, and yet we must constantly take it in to survive.)
 P: 4 Okay I have a much better idea of what's going on now, even though it's very superficial it's a better start none the less. Thanks to all who replied.
HW Helper
P: 6,164
 Quote by DaveC426913 As Yanick points out for example, most of your body weight is water.
Uhh...
Mentor
P: 37,664
 Quote by I like Serena Uhh...
It's just that the two of you look so much alike!
 P: 41 Ask any bodybuilder trying to move up a weightclass ( If they're moving up a weight class they need to come in at the top of it to win. So your looking at a good 15 to 20 LB gain in lean mass) how much time they spend in the bathroom. I assure you its quite a bit.
P: 15,294
 Quote by I like Serena Uhh...
D'oh!

Fixed.

(Wow. 11 hours later I can still edit.)
PF Patron
P: 641
 Quote by Yanick A calorie is a calorie, though lots of people in the diet and fitness industry like to argue this fact. In the end though a calorie is a calorie.
I agree. Feinman and Fine's papers were used by some to claim otherwise:

 Reduced thermodynamic efficiency will result in increased weight loss. The laws of thermodynamics are silent on the existence of variable thermodynamic efficiency in metabolic processes. Therefore such variability is permitted and can be related to differences in weight lost. The existence of variable efficiency and metabolic advantage is therefore an empiric question rather than a theoretical one, confirmed by many experimental isocaloric studies, pending a properly performed meta-analysis. Mechanisms are as yet unknown, but plausible mechanisms at the metabolic level are proposed.
Thermodynamics of weight loss diets
http://www.nutritionandmetabolism.co...-7075-1-15.pdf

But here is a summary of the research suggesting that Feinman's and Fine's arguments are not warranted:

 We thank Manninen and Feinman and Fine for their interest in our review, "Is a Calorie a Calorie?" . These 2 letters correctly point out that there are indeed some differences between the energetics of human metabolism and the measures of heat release of nutrients in a bomb calorimeter. We agree with the known concept that the metabolic route through which carbon flows to carbon dioxide, the concentrations of substrates, as well as entropy can all slightly alter the efficiency of ATP production in humans. This concept, however, does not automatically mean that these differences constitute a quantitatively plausible mechanism that would explain the differences in weight loss observed with a high-protein, energy-restricted diet relative to a low-fat, energy-restricted diet. Rather than relying on a theoretical treatment of metabolic efficiencies, as did Feinman and Fine, we reviewed studies in which known experimental diets were fed to subjects under laboratory conditions to test whether energy expenditure was actually higher with a low-carbohydrate diet than with a high-fat diet. In studies in which protein intake was held constant and fat was substituted for carbohydrate, the difference in 24-h energy expenditure between the high-carbohydrate and high-fat diets was not different from zero . However, as clearly stated in our review, when the protein intake was not held constant but rather increased from 15% to 30-35% of energy, 24-h energy expenditure did increase. We determined, however, that the increase would be only 41 kcal/d for a 1500-kcal/d energy-restricted diet. This would only increase weight loss by 0.04 kg/wk, or 0.44 kg over a 12-wk course of weight-loss treatment. It should be noted that this is less than the 95 kcal/d calculated theoretically by Feinman and Fine, and it has the advantage of being based on experimental data. Thus, we do not disagree with Feinman and Fine from the perspective of pure thermodynamics; in fact, we resented evidence at the whole-body level that supports their point. However, we found the experimentally measured differences in 24-h energy expenditure, between subjects who followed a high-protein diet compared with those who followed a high-carbohydrate diet, to be too small to satisfactorily account for the differences in weight loss observed after 12 wk of treatment with these 2 diets. Thus, this is not a plausible mechanism to account for the observed increased weight loss. The experimental data on energy expenditure provide evidence of only a minimal metabolic advantage for low-carbohydrate diets.
 In addition, we concede that the substitution of one macronutrient for another has been shown in some studies to have a statistically significant effect on the expenditure half of the energy balance equation. This has been observed most often for high-protein diets. Evidence indicates, however, that the difference in energy expenditure is small and can potentially account for less than one-third of the differences in weight loss that have been reported between high-protein or low-carbohydrate diets and high-carbohydrate or low-fat diets. As such, a calorie is a calorie.
Is a calorie a calorie?
http://www.ajcn.org/content/79/5/899S.full.pdf

http://conditioningresearch.blogspot...re-taubes.html
 P: 3 Calories between 2700 to 3000 are the causes of weight gain. If you eat more calories and burn less calories then it is the causes of weight gain. Do properly exercise for 30 mints daily and other activities like swimming, running, jugging, walk etc. Use fresh fruits and green foods items helps to in weight management. It change body figure and life style.
 P: 2 The calories amount doesn't matter in weight gain only if you are burning the calories regularly with some workout plan.Also try to consume less then 2500 calories daily.Because if you'll take more than that then you should have to do heavier workout plan for burning the calories.

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