For one thing, it is not exactly the same in all people.NightFaLL wrote:That's where the misconception happens - people aren't gaining weight because of carbs, they're gaining weight because of excess calories.Stephen Johnson wrote:With the epidemic of obesity in the US over the last 20 or so years - which curiously coincides with a push towards low fat (ie high carb) foods from fatty foods - the pathways you mentioned, sadly, don't appear to be inefficient enough.NightFaLL wrote:Either way, having metabolic syndrome can't cause efficiencies in fat storage that aren't there. The pathways used to convert glucose to lipids is inefficient from what i've read.
When you intake carbohydrates and fat, it causes fat oxidation to essentially stop - this means that if you're eating at maintenance the fat calories temporarily are stored as fat, once the carb calories stop being used - the fat that was stored is then released for energy.
Hence, energy balance.
When you intake carbohydrates and fat, and you're above caloric maintenance for the day - the fat is stored and never used, due to the fact you have an abundance of calories from carbohydrates.
So, essentially - it is actually the fat and carbs in a combination with a caloric surplus that is making american fat.
The main reason it has come along with the 'low fat' craze is because people don't pay attention to calories when things say low fat - the just eat as much as they want.
It is both calories and carbs that lead to weight gain. Or at least they are associated with weight gain.
More carbs means more insulin, which will shuttle more calories into the fat stores.
When you eat carbs it is turned into glucose and fatty acids. Any extra glucose is converted into triglycerides and stored as fat. What you stated is only true WHEN YOU ARE NOT IN A CALORIE SURPLUS. I don't know how much more clear that can be. Carbs are a very efficient energy source. You use them or they get stored as fat. Period.
Because of how quickly some carbs are digested, you have very little time to use the energy. So while you might not be in calorie surplus over the day in total, you ARE in calorie surplus for periods of time after a meal.
Try eating 2000 calories of veggies, then try eating 2000 calories of donuts. You will notice a difference.
Finally for some people the cause is actually the weight gain and the effect is overeating. Here is how it works, at least for people with some sort of metabolic problem or poor genetics. Your body preferentially shuttles food to fat stores. The rest of your cells are starving, so your appetite is increased and you also have very little energy. This can sometimes be fixed by reducing insulin levels. But just eating less won't work for a person in this situation. They will simply become more lethargic.
There is also a peptide that has something to do with this whole process. It has been approved recently to treat diabetes, but it works for weight loss too. We don't even understand most of what this peptide does. So it's really silly to pretend like we have absolute certainty.
It's also never been established that weight gain and overeating have a cause/effect relationship. Only an association has been proven.
One way to think of it is that in some people their fat stores are like a greedy mob boss. They skim off the top. If you're body wants to stay in business it has to bring in more money, or it will find itself with only enough to pay the rent and no spending cash.
You would if you could. However that would be extremely difficult. It also depends on what you are comparing it too. As I mentioned earlier, simple carbs are digested quickly. So you could break even over the course of the day, but still gain weight because of periods of being in calorie surplus.I guarantee that if you were to eat 500 calories over maintenance every day for a week on fat/protein, you would gain a significant amount of fat.
If you take anything away from this, it should be that this whole thing is nowhere near as simple as you think it is. It is exponentially more complicated. People are different too.