The Wrong Eating Habits Can Hurt Your Brain, Not Just Your Waistline | Hacker News Reader

The Wrong Eating Habits Can Hurt Your Brain, Not Just Your Waistline

npr.org

96 pointschang230137 comments

> He says something similar may happen in human brains when people eat a diet high in fat and sugar. Davidson says there's a vicious cycle of bad diets and brain changes. He points to a 2015 study in the Journal of Pediatrics that found obese children performed more poorly on memory tasks that test the hippocampus compared with kids who weren't overweight.

These assertions raise doubts in my mind regarding the study as a whole. Fat and sugar (a carbohydrate) account for two of the three most common macronutrients, the third being protein. Eating a diet that's low in both fat and carbs would imply a mostly-protein diet which can lead to illness[0].

The further implication that a particular macronutrient ratio could cause obesity is particularly concerning. Weight gain/loss is determined strictly by whether someone consumes more or fewer calories than their body burns in a day. The ratio of macronutrients may effect other health indicators like lean body mass, but a diet of 100% sugar and fat will still lead to weight loss if the total caloric intake is lower than what the body requires thereby requiring the body to burn muscle/fat for energy[1].

While the researchers have found a correlation between memory function and obesity, they appear to be making spurious claims that the foods the obese people eat are a contributing factor. There's no indication they made any attempt to control for the fact that healthy people also regularly enjoy ice cream and bacon, just at a lesser rate than those who are chronic over-eaters and therefore obese.

[0] https://en.wikipedia.org/wiki/Protein_poisoning [1] http://articles.latimes.com/2010/dec/06/health/la-he-fitness...

> The further implication that a particular macronutrient ratio could cause obesity is particularly concerning. Weight gain/loss is determined strictly by whether someone consumes more or fewer calories than their body burns in a day. The ratio of macronutrients may effect other health indicators like lean body mass, but a diet of 100% sugar and fat will still lead to weight loss if the total caloric intake is lower than what the body requires thereby requiring the body to burn muscle/fat for energy[1].

Perhaps, but people in the real world don't usually carefully measure out a portion based on calories before consuming; they eat until they're not hungry anymore. So any food that is calorically dense but doesn't satisfy hunger is likely to contribute to obesity.

The government warns against fats and sugars for similar reasons here https://health.gov/dietaryguidelines/dga2010/dietaryguidelin...

Fats are pretty damn filling, even when caloric density is accounted for, at least for me.

Well I think that's a big part of why the focus lately is moving to sugars over fats. But the other point is that they're not very rich in nutrients.

Unsaturated fats are essential for brain function & health. Increased consumption has been linked to a reduced risk of dementia and Alzheimers.

It's saturated fats and trans fats in particular that everybody is warning you off, not lipids altogether.

This is the "a calorie is a calorie is a calorie" argument, and it's not true. Sugar upsets the metabolic process in disconcerting ways, leading to fat accumulation and insulin resistance; sugar is also more addictive than cocaine[0]. Meaning that when you consume calories from sugar, you crave more sugar calories. The foods you eat do make a difference in how fat you get, because they alter your metabolism and behavior -- but Western foods are so loaded with added sugar that sugar becomes difficult to control for.

[0] https://www.ncbi.nlm.nih.gov/pubmed/23719144

Yes, macro break down, thyroid issues, metabolism, illness, meal timing, GI, insulin spikes, hormone levels etc do make a difference. To grab at a generous figure lets say they make up 25% of the puzzle. With calories in VS calories out been 75%. And i think that 25% is very, very generous.

Stating calories in VS calories out is not true because of X, Y or Z is like building a house by starting with the doorbell. Before you lay the foundations. Fundamentals before details.

The "calorie is a calorie" argument is true in that

    weight gain/loss == surplus/deficit intake

Your point about sugar fucking with insulin balance and its addictive properties are good points, but not directly related to the study at hand. Western prepared foods are loaded with added sugar, but it's completely possible for obese people to eat a complete diet of home-cooked meals in surplus using only fresh, raw ingredients without a gram of added sugar. It's also completely possible for skinny people to eat shit food and not get fat. The researchers should have controlled for body fat % and diet, which would not have been challenging. Instead it seems they've chosen to completely conflate the two key factors.

> Fat and sugar (a carbohydrate) account for two of the three most common macronutrients, the third being protein. Eating a diet that's low in both fat and carbs would imply a mostly-protein diet which can lead to illness

Spot-on observation. Furthermore, while proteins can be metabolized for energy, that's not advisable as a major energy source, proteins should be spared for day-to-day repairs (most-all multicellular structures ---incl tissues/bones/organs/tendons, the brain, not just simply "the muscles"--- are constantly tearing-down and rebuilding and we also synthesize much other crucial stuff partially from amino acids, red/white blood cells, enzymes, the list goes on, even glucose if&as necessary) and burning them instead not just removes them as building materials but also creates various additional stresses on the body, produces extra detrimental waste products to be run through the kidneys and get excreted, etc.

All mammals excel at beta-oxidation of both carbohydrates and fatty acids for energy, I know of no animal thriving off the meagre amount of energy their bodies may safely obtain from proteins. Many humans don't seem do particularly well (in the long run) combining fats & carbs in ~equally high amounts and find better results emphasizing one and sharply reducing the other. (Personally I'm a fat advocate but no need to get into that discussion ;)

Consider 2000kcals from protein-only (not that your body will allow this) would require 500g of protein, so about ~2kg of super-lean meat or over 100 egg-whites.. and that's not yet counting any protein usage as building-blocks!

There's a huge difference between various carbs. In the 90s both Japan and developing countries in east Asia had absolutely massive rice intakes and extremely low rates of obesity, and high longevity.

According to studies I've read, many people got 1/2 to 2/3 of their total calories just from rice. You can't do that with sugar and lead the world in longevity rates.

This falls into the category of "things I didn't know, but I assumed anyway."

I don't know why the brain and body are still presented as being so distant-- it's all one system!

If you're treating your body poorly, how is that not going to negatively effect the most important and complex organ of said body?

Yeah that makes sense, but since the body is a complex system, it _would_ be possible that something like the following is going on. This is fictional, but _could_ be true, if we didn't know otherwise.

Your body prioritizes certain organs and bodily functions over others, depending on the resources that it gets. Who knows, perhaps when the body recognizes that it's not getting enough of a certain vitamin, it will change how it distributes the vitamin throughout the body. Now, because of evolutionary reasons, a function evolved that when the body recognizes the brain is getting too little of a certain vitamin, it takes a larger portion of what _is_ coming in, to make sure that the brain functions properly so it can solve the issue of poor diet, making a cut elsewhere in the body.

Of course, this is utter bullcrap, but it _could_ have been true.

Though, I'm completely with you, this is something I always assumed as well.

I think this has much to do with commercial interests.. if there where a higher stigma around the actual cognitive effects of junk-food and sugar it could generate fewer sales.

A fitting Terrance McKenna quote:

We do not think of ourselves as a meat/sugar/alcohol culture. People do not walk around saying "Oh wow, I'm so high on meat, alcohol and sugar!" but they ARE!

My takeaway from Michael Pollan's books was that we are essentially a corn culture, but a "meat/sugar/alcohol culture" works too I suppose.

> the most important

The most important organ, eh? Consider the source of that information. ;)

This assumes that overeating is bad for the body. We know it is because did is readily available, always. But in a world where did may go away for weeks at a time this overeating may be optimal and hence good for the brain too.

I'm not seeing how this evidence points to overeating --> brain impairment. To me it implies brain impairment --> overeating.

> He did that by studying rats that had very specific types of hippocampal damage and seeing what happened to them.

This researcher started with mice that had damage, and observed they overate. This implies brain impairment --> overeating. The other memory studies in the article with obese or lean subjects cannot infer causality.

> However, even though we are beginning to understand that obesity affects the brain, we don't exactly know how [...]

Perhaps the connection is people with brain impairment (either genetic or damage from the environment) tend to overeat, since the brain plays a role in hunger and satiation. Is there evidence that the article omits that backs up the headline?

It doesn't directly imply that brain impairment causes overeating either. Perhaps something else is causing both. Causation is hard.

That's true- and on that note I wonder if it's the gut in general and it's all related in a cycle. (Given the compounding evidence your gut directly affects your brain.)

From http://www.hopkinsmedicine.org/health/healthy_aging/healthy_...: "For decades, researchers and doctors thought that anxiety and depression contributed to these problems. But our studies and others show that it may also be the other way around," Pasricha says.

I don't buy that they "forgot they were full" because of diminished short term memory. When people overeat, I do not buy that it is because they actually forgot that they already ate.

Some other brain effect could make sense, but this one seems weak.

They are talking about the rats, with people, it's the fact that people don't feel full - they still feel hungry, so they continue to eat.

How do you know it's not the same for the rats? :P

IIRC around 20-30% obese people have ADHD, and they use food as a form of self-medication when their dopamine levels get low.

Unfortunately it's not screened for in obese people, so most of them never get tested :(

Myself, once I began meds, the need to eat constantly evaporated. The first month I felt no hunger whatsoever (I guess there was no dopamine deficiency any more, and regular hunger systems still haven't kicked in), and after that time my hunger got to normal levels - meaning, the weight stabilised, and now I eat only when truly hungry.

I notice a moderate effect on my cognitive ability due to weekly or monthly alcohol consumption (longer term than the hangover cycle). There have been a few times in my life (such as when studying for my PhD comprehensive exams) that I quit drinking completely for over a month and I was quite surprised at how much more clarity of thought and memory I had. Not enough to make me abstain from drinking altogether, but enough that it's helped me drink substantially less.

This could also be related to sleep.

- Alcohol reduces the quality of your sleep, so you'll likely be playing catch-up regularly if you drink regularly before bed.

- Removing alcohol often removes the social situations surrounding alcohol, such as going out drinking till late. This means less alcohol will help stabilize your sleep cycle and keep you from spending too many nights out late.

I found that (during a difficult undergraduate course) sticking to a strict sleep schedule (and getting sufficient sunlight in the mornings) had a very positive effect on my cognitive ability.

People reeeeally overestimate just how many drinks and with what frequency it takes to cross into that "it's negatively affecting my health" threshold.

The mayo clinic recommends these standards

Up to one drink a day for women of all ages.

Up to one drink a day for men older than age 65.

Up to two drinks a day for men age 65 and younger.

The limit for men is higher because men generally weigh more and have more of an enzyme that metabolizes alcohol than women do.

A drink is defined as:

12 ounces (355 milliliters, or mL) of beer

5 ounces (148 mL) of wine

1.5 ounces (44 mL) of 80-proof distilled spirits

Most people from my experience:

- Pour a glass of wine way over 5 ounces - Drink pints of beer at the bar, which are 16 oz, not 12, and drink at least 2 or 3.

The moderate part is the key, both in frequency, and amount. Not drinking all week, then binge drinking is worse than simply drinking one drink every day of the week.

Indeed...furthermore, people severely overestimate the amount of calories they burn through exercise and vastly underestimate the amount of calories they consume.

> 12 ounces (355 milliliters, or mL) of beer

Specifically, at 5% ABV. Big difference between 12oz of light lager and 12oz of barleywine.

Assuming sugars and all saturated fats are both equally to blame is not in tune with modern research, though of course a lot of competing voices exist.

Saturated fat in itself is not the problem. Caloric excess in the form of saturated fat is. Athletes consume more saturated fat because it increases testosterone production (https://www.ncbi.nlm.nih.gov/pubmed/9029197?dopt=Abstract)

A hamburger won't kill you. A hamburger if you live a sedentary lifestyle will.

Also, a single hamburger will not kill you. Eating 5 Guys for lunch every day is going to be a problem.

This stood out to me, as well. I don't think everyone fits the mold that any one macro group is good or bad because I think it depends on our gut bacteria (which is potentially as unique as a fingerprint[0]).

I don't deny calories in > calories burnt leads to weight gain but to put it that simply does a disservice to educating people about their bodies and completely ignores the hormones controlling fat storage. "researchers at the National Institutes of Health have shown how insulin prompts fat cells to take in glucose in a rat model". [1]

So does calories in being higher than calories burnt lead to weight gain? Sure. That's thermodynamics. But what about lots of carbs in the diet (even paired with fats) and how that causes a higher insulin response and that then causes easier / more fat storage. I think the research here is clear and compelling. Of course, some people, due to their guts just may not process food the same way and may break it down more completely or be less sensitive to carbs in general.

"In general, the gut microbiota found in obese youth tended to be more efficient at converting carbohydrates to fat compared to the gut flora of normal-weight individuals. This suggests that even with similar caloric intake, obese youth are accumulating more fat compared to lean youth as a result of the composition of their gut microbiota." [1]

[0] https://www.hsph.harvard.edu/news/press-releases/personal-mi...

[1] https://www.nih.gov/news-events/news-releases/nih-study-show...

[2] http://www.livescience.com/56179-gut-bacteria-differ-in-obes...

To be frank I think studies like this give some people an excuse. They become wrapped up in all the other factors beside calories (macro break down, genetics, hormone levels, GI, insulin spikes, meal timing, illness etc) yet ignore what is by far the biggest part of the pie (terrible pun, my apologies) - calories.

Having been on a ketogentic diet (low carbs, high fat) for the last 5 months or so, this is in line with what I've seen.

I went on the diet because of the promise of a clearer head, as well as general health improvement. It made sense, as I'd been plotting my work efficiency with and without sugary products. The complete removal of all carbs has done nothing but improve my life.

The carb addiction component mentioned elsewhere lines up as well. At the beginning of the diet, there's a period called the keto flu that lasts a couple weeks. It's described as mental fogging, headaches, dehydration, etc. While this is also attributed to the switching of metabolic pathways (more water and electrolytes are needed daily), the effects were very similar to caffeine withdrawal.

And of course I indulged in sugar through the holidays, and found myself figuratively face down in a gutter each time ;)

At first the article claims that saturated fats and sugars are to blame, but then all the evidence discusses obesity regardless of diet composition and claims we don't understand the mechanisms. Not a well written article...

Hire someone overweight who might have issues with stress, memory, may require additional time off due to health issues or hire someone who looks relatively healthy. If not explicitly, implicitly this type of discrimination must happen.

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