[iforgotpassword]

Honest question: how? I've never seen anyone who's obese and having a diet that made me go "huh that's odd how can they be obese?"

While the inverse occasionally has been true, generally people who I consider in good shape appear to eat less, and less greasy food.

So while there might be exceptions it seems to be a damn good rule of thumb to me.

[ggm]

Because of homeostasis: dissolved substances like fats in the bloodstream are regulated within bands, and beyond certain limits the amount ingested doesn't translate to more: it's excreted or winds up elsewhere. Your metabolism may cause states worse than other people, sure. But that pound of butter you ingested isn't directly causing rises in the bloodstream to infinity. It's long-term accumulated burden and excess over time.

Cholesterol levels don't track intake directly. Lowering cholesterol and fat in diet needs to be done in consultation with somebody who understands your metabolism. Some vitamins are fat soluble. Some fat is beneficial.

Homeostasis is amazing.

[cassepipe]

While I always knew that sugars where the main culprit for body fat thanks to a highschool biology class, I have never understood why fat is less of a problem so thank you. Could you link me with sources or search keyword in order to know more of what the body is doing with excess fat ?

[ggm]

I tried "what does the body do with excess fat" and I think it covers it. For sure, you get higher triglycerides floating around in the bloodstream, and the liver is under stress. at the extreme end, its Steatorrhea which is .. unpleasant (olestra goes to the same place)

The lymphatic system is also involved.

So it's not entirely "eat as much fat as you like" by any stretch. It's more that over time, the body tends back to a baseline model. Continual high levels of fat which cause surplus in the bloodstream are heading to arterial blockage and isn't good, but the relationship of fat ingested to fats in the blood is a more complex path. "it depends"

I'm not a bio scientist or a med. Happy to be corrected.

[zamalek]

> I've never seen anyone who's obese and having a diet that made me go "huh that's odd how can they be obese?"

Are they eating fat _or sugar?_ The body will aggressively squirrel away any unused sugar as fat. As one example, a Big Mac contains 7g of _added_ sugar. Fries? Coated in dextrose. Sugar is added to damn-near everything.

[TylerLives]

"Starch and glucose efficiently stimulate insulin secretion, and that accelerates the disposition of glucose, activating its conversion to glycogen and fat, as well as its oxidation. Fructose inhibits the stimulation of insulin by glucose, so this means that eating ordinary sugar, sucrose (a disaccharide, consisting of glucose and fructose), in place of starch, will reduce the tendency to store fat. Eating “complex carbohydrates,” rather than sugars, is a reasonable way to promote obesity. Eating starch, by increasing insulin and lowering the blood sugar, stimulates the appetite, causing a person to eat more, so the effect on fat production becomes much larger than when equal amounts of sugar and starch are eaten" From https://raypeat.com/articles/articles/glycemia.shtml

[cassepipe]

Where I live, there's only one beer brand that does not have glucose syrup. Sad.

[jcul]

Just guessing as to the parent comments meaning.

But I suppose that plenty of fats are healthy and part of a balanced diet. And someone who eats nothing but refined sugar is more likely to be over weight that someone with a high % of fat in their diet.

[Hedepig]

I think you're right

The danger is two fold

1. People don't eat fatty foods which have solid evidence for their benefits (e.g. Virgin olive oil)

2. People substitute the lack of fats with sugar, which I believe (not an expert) has a lot literature linking it with obesity

[brettv2]

> I've never seen anyone who's obese and having a diet that made me go "huh that's odd how can they be obese?"

Your question isn't refuting OPs claim: the people you are observing to be fat are fat because of their carb/sugar intake, not fat.

i.e. if you just fed someone large amounts of protein and fat they would be lean; it is the sugar and carbs that make them fat.

[jlhf]

No they wouldn’t stay lean. If you fed someone more calories than their body uses to maintain its current weight, they would get fat eventually. Regardless of whether they eat carbs, fat or protein.

[kuschkufan]

Let's say you're being fed just the amount of calories your body needs to maintain. What influence on body fat has the distribution of carbs, protein and fat from food then?

[jlhf]

My point was that regardless of what you eat, if you eat more than your body expends, some of the excess will be used to produce fat and you will gain weight. If you lead a sedentary lifestyle and eat 3000 calories of nothing but lean meat per day, you will gain weight.

You are right that different foods (macronutrients, more specifically) have different thermic effects and therefore require different amounts of energy to metabolise. Protein takes more energy to process than fat. This does not change my overall point.

[lobocinza]

Not much for getting lean but it's easier to overeat carbs and fats are calorie dense. That said you need to eat a mix of the three to be healthy because they all have important body functions.

[burjui]

Lack of carbs supresses appetite, JFYI.

[jlhf]

I never claimed otherwise and it does not negate my point.

[jbd0]

You're so wrong. With only protein and fat, they would not be able to gain much weight. I've tried to gain weight on low carb/high fat, and it doesn't work. I was uncomfortably full after every meal. My tracking showed a significant calorie surplus, but my body wasn't absorbing it. Adding in more carbs made a huge difference. Hormones tell your body when to store fat.

[Attummm]

Did you know that bodybuilders in the 1950's(before anabolic steroids) used the egg and steak diet before contests as cutting diet to get lean? They would eat, as the name suggests, large quantities of steak and eggs with butter and have a carb refeeding day every 4 days. They would get really lean on a very high-calorie diet, think 4000 to 6000 calories.

The inventor of diet famously lost a contest for being too lean.

[callmeal]

> if you just fed someone large amounts of protein and fat they would be lean;

A large amount of protein would make them fat - experiments have shown that about 8% of ingested protein gets converted to glucose in the liver:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636610/

    The authors calculated that ∼18 g (79%) of the 23 g of ingested protein could be accounted for by deamination; thus those carbon skeletons were available for gluconeogenesis and release of new glucose into the circulation. The remainder, presumably, was used for new protein synthesis.

    The total amount of glucose entering the circulation from all sources was calculated to be 50 g over the 8-h period. However, only 4 g (8%) could be attributed to the ingested protein.

[amanaplanacanal]

I think you misread that experiment. It appears that some quantity of protein was converted to glucose, but that it wasn’t dependent in the quantity of protein consumed.

[cies]

Humans are bad at lipogenesis: we can only convert tiny fraction of the carbs into fat. Thus: the fat your eat is largely the fat you wear.

You cannot explain it otherwise (without showing a undiscoverd way humans can convert carbs into fat).

> i.e. if you just fed someone large amounts of protein and fat they would be lean; it is the sugar and carbs that make them fat.

This is dangerous. It may work on the short term, but it is very dangerous on the long run.

[mpreda]

> Humans are bad at lipogenesis: we can only convert tiny fraction of the carbs into fat.

Because historically food is scarce or difficult to obtain, in general organisms develop mechanisms to make good use of it: when excess food ("energy") is available, it is stored rather than wasted.

This is also true in particular for mammals, and for humans. It's quite obvious that humans are very effective at storing excess energy.

It is said that sumo fighters maintain their body mass (muscle + lots of fat) by eating rice (i.e. carbohydrates) and protein.

Lipogenesis (fat generation from carbohydrates) takes place mostly in the liver. "Excess acetyl CoA generated from excess glucose or carbohydrate ingestion can be used for fatty acid synthesis or lipogenesis."

https://courses.lumenlearning.com/suny-ap2/chapter/lipid-met...

The conclusion being: "Humans are great at lipogenesis. That's how we store excess energy."

[cies]

Nope. If humans eat both carbs and fat (most of us do), the excess calories of fat goes mainly into the storage (or plaques to your arteries), while the carbs are used in the sort term (converted into glucose).

> Lipogenesis is mostly derived from carbohydrates and is a relatively minor contributor to whole-body lipid stores, contributing 1–3% of the total fat balance in humans consuming a typical diet.

From:

https://www.sciencedirect.com/topics/agricultural-and-biolog...

Believe what you will. "It is said" wrt sumo fighters does not sound very scientific.

[Attummm]

The human body doesn't need to store excess calories. It could store the excess calories or it can excrete energy through urine(glucose, ketones) Or it can ramp up metabolism, there are many scenarios. Not all lead to adipose tissue growth. Why not muscle growth, which is somehow always overlooked in these discussions.

Funny enough adipose tissue and muscle growth are both through hormones. If testorone and hgh are high then muscles growth will prioritised over adipose tissue.

People with type 1 diabetes have figured out how to stay thin after eating copious amounts[0]. They won't inject themselves with insulin. Unhealthy, sure, but they won't store calories, as adipose tissue (fat cells) remain inactive, even though blood glucose is dangerously high.

Just looking at calories is simplification, and is just for general guidance.

[0]https://my.clevelandclinic.org/health/diseases/22658-diabuli...

[Attummm]

Why would a mammal's body evolved to use fat cells to store and utilise lipids for energy?

Plants have carbs in starch. Mammals evolved away from starch to store and use triglycerides.

During fasting, the human body is able to survive for months without food.

Thus months of lipid metabolism

[cies]

> Why would a mammal's body evolved to use fat cells to store and utilise lipids for energy?

Hibernation?

For short term glucose storage is preferred by mammals bodies that i know of.

[thelittleone]

High fat and protein is keto right? What's so dangerous?

[cies]

Ketosis is probably our rudimentary "wintersleep mode". Rudimentary as we are basically tropical animals (look at our lack of fur).

We should not eat for ketosis. But we can eat (restricted to fat and protein) and still stay in ketosis, which is marketed as the keto diet and is not well tested in long term studies. You are a guinea pig when you do this long term.

[imtringued]

>You are a guinea pig when you do this long term.

As opposed to being reliably obese? What's your baseline? I recently checked the average weight of men and women and I am honestly shocked.

[cies]

Short term you can lose weight with ketosis. Long term you are taking unknown risks.

The risks of obesity are well known. Also, you do not get obese by lack of a keto diet. One usually gets there with a rubbish diet.

[dimask]

"Being fat" and having too much fat (or the wrong kind of fat) in the blood or brain are not equivalent. Eg people with high cholesterol can be quite slim also.

[imtringued]

Your body can't take fat from plants and animals and directly embed it into fat calls. The metabolism of ingested fat takes much more steps than say sugar, which can be directly absorbed into fat cells and also raises insulin resistance. Sugar and refined carbohydrates are a far bigger reason for obesity than fat consumption or "greasy food".

[simonbarker87]

People get fat through consuming more calories than they burn for energy during the day. There are extra but around the edges but no matter the ratio of fat to carbs to protein, if someone consumes (food or liquid) 3,000 calories a day but only burns 2,500 calories a day then a decent portion of that 500 cal difference will get stored as body fat. You could eat 0 calories of fat but if that total of carbs and protein is over your energy burn then over time you will add body fat.

I believe most people gain excess body fat through eating a little bit more than they need each day and then two or three weeks a year they eat and drink much more (holiday, Xmas, birthday etc), rather than consuming vast amounts of food day in day out of the wrong macro nutrient make up.

[_heimdall]

The calorie hypothesis isn't the most likely from all the research I've done. The calorie as a unit of measure doesn't even make much sense IMO.

A calorie is measured by burning food a specific distance away from a specific amount of water and measuring how much the water temperature rises. It's based on an assumption that the body uses all energy in the food the same, and that fire is analogous to the complex process from digestion to energy use in the cell. The calorie as a measure effectively equates the body to a coal power plant.

[simonbarker87]

Which the body basically is.

Anyone who tracks their calories daily for a long period of time will see that when they eat more they gain weight, when they eat less they loose weight.

Like I said above, there are other aspects that can factor but “calories in calories out” accounts for 80% of weight loss and weight gain (applying the broad brush of the 80:20 rule)

[_heimdall]

If a calorie is a calorie, would you agree that I would be just as well of eating 1800 calories of fat rather than a balanced diet? Could I stick to 1800 calories of gasoline?

We can't simply burn food and deem that an accurate analog to how the body processes and utilizes different food. Ask anyone that live(d) primarily on rabbit meat.

And to be clear, the 80:20 rule is am extremely broad and inaccurate rule of thumb that isn't useful when applied to something specific. You can't claim that calories in equals 80% of calories out because Paredo.

[funcDropShadow]

> “calories in calories out” accounts for 80% of weight loss and weight gain

That is simply not true for people that are already obese.

[francisofascii]

But it does depend on the type of foods. For example, let's take a serving of almonds listed at 160 calories. Your body may only absorb 120 (depends on the person) of those calories to be burned due to the fiber in the almonds. While foods with sugar and little fiber, you get close to 100% of the listed calories.

[simonbarker87]

Sure, and that kind of thing falls into the 20% of the 80:20 rule of most things. The vast majority of people loose or gain weight based on their calorie in take / expenditure

[earthling8118]

This is counter to the point that was made regarding fat. The almonds have a higher ratio of fat to other macros.