What will make you fatter...?

Well if it's not a tricky question, I'd say fat ; since calories from carbohydrates needs to be converted to triglycerides before they can be stored as body fat. The conversion uses around 25% of the energy coming from the food. That means in your case, with 1000 calories of pure carbohydrates in excess, only 750 calories worth of fat would be used.
Fat in one another hand requires around 3%, meaning in our case, around 970 calories stored as fat.
Now if the question is about the absolute energetic value, well, 1000 calories in excess are 1000 calories

This. Realistically though, it's not a huge difference over the span of a month, about 2 lbs.

Let's assume you are currently maintaining on 2,000 calories a day 50/30/20 C/F/P and you were to overeat consistently by 1,000 calories of either pure carbs or pure fat for a month, which would make you fatter, or would there be no difference and why?

Curious as to what people think. I've seen people state that anything over 15g of cho in a meal will be stored as fat or that fat makes you fat etc etc. So which is worse to overeat, carbs or fats or does it not matter?

Assuming there's no knock-on effect on the metabolism from eating one form of food over the other (like you get really sleepy or jittery or something), I'd say that both the ton of feathers and the ton of bowling balls will weigh the same... no difference.

Let's assume you are currently maintaining on 2,000 calories a day 50/30/20 C/F/P and you were to overeat consistently by 1,000 calories of either pure carbs or pure fat for a month, which would make you fatter, or would there be no difference and why?

Curious as to what people think. I've seen people state that anything over 15g of cho in a meal will be stored as fat or that fat makes you fat etc etc. So which is worse to overeat, carbs or fats or does it not matter?

Besides dying from lack of amino acids? :laugh:

I really like that so many people are curious about this. One of the first things I will say is that there are a LOT of valid points out there (I was going to repost them as I was going through, but then realized that would take too long lol). Second, 1000 calories IS 1000 calories, no matter what the source. However, calories are only a measurement of energy, not amount of food consumed, so to say that you have consumed the same amount of food in either case is INCORRECT. In actuality, you have consumed roughly 3.91 oz of fat, but 8.82 oz of CHO! That is over twice as much CHO than fat. Does that mean the CHO will make you fatter? I agree that is not so clear cut. They are the body's fuel-of-choice, and they can be converted to glycogen if stores are less than full (in either the liver or muscle tissue), but it can still be converted to fat if those stores are full or your intake of another macronutrient exceeds that of CHO. Age, fitness level, and type of exercise can all affect how these nutrients are utilized (along with many other factors

Id say carbs. Just watched this about carbs and insulin

http://m.youtube.com/#/watch?desktop_uri=/watch?v=mNYlIcXynwE&feature=youtu.be&feature=youtu.be&v=mNYlIcXynwE&gl=US

I have no ****ing idea, nor do I care. Under calorie goal = happy.

I've been told by doctors that you really shouldn't pay attention to the fat labels on the nutrition label. Carbs is a HUGE factor in weight gain. Hence the reason a lot of people try to go on a no carb diet. However that usually fails...your body still needs carbs. But my mother had to go by carbs due to diabetes issues...she lost over 100lbs. in less than a year from it...and healthily.

I guess if you eat 1000 calories, you eat 1000 calories. I don't think it matters.

Changed my mind:

But, if you were eating less than 20g of carbs a day, you would lose weight if you ate the 1000 additional calories of just fat. Been there, done that. Dr Adkins

Which weighs more ... a pound of feathers or a pound of lead?
They both weigh a pound, but if they fall on you, the more compact pound of lead would probably do more damage.

There are mixed opinions on whether calories' source makes a difference. Based on what I've seen, my guess is that they'd both increase your weight by the same amount, but as they are likely to provide different nutritional content, over the long-term, they might have different health consequences.

??

Luckily such a study on this has been done, although there have been some good points made in this thread that likely could lead to different results then this study found.

Horton TJ, et al. Fat and carbohydrate overfeeding in humans: different effects on energy storage. American Journal of Clinical Nutrition, 1995; 62: 19-29.

www.ajcn.org/content/62/1/19.full.pdf

Excerpts from research omitted. Thanks for bringing actual research results into the conversation!

Shouldn't the weight gain be the same? Whether it's a 1,000 calorie surplus in protein, fat, or carbs...it's still a surplus

I didn't read all the earlier posts, so I apologize if this was already said, but I would think the carbs would make one fatter. Reason being, ingested fat != body fat. If I ate a bunch of fat, I would think my body would assume I will continue this, and would therefore release hormones to burn body fat. If I ate carbs (to a surplus, therefore I didn't burn them all), my hormones would say "turn those carbs into fat!"

I could be, and probably am, quite wrong in all this, as my background in nutrition is limited to Google, this forum, and my grade 10 teacher.

The real answer is:

Beer will make me fatter.

It won't matter...on the molecular level they are equivalent to one another. With carbs they are the prefered fuel because they are broken down quickly to be utilized, fats take longer to break down to use. However add to much of either and it still just gets bypassed and stored in the fat cells.
Time had a basic article on this very thing...

http://www.time.com/time/health/article/0,8599,1822118,00.html

Oh yes o/