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Comment by CGMthrowaway | Hacker News Reader

>I was wondering how you could get such a high impact overall. But it seems one in 6 households are on GLP-1 drugs in the US.

I had the same question and did some back of the envelope math. The data I have seen says the average American eats 400-700 excess daily calories, and 3600 daily calories total. That means 10-20% excess per person. If everyone started eating the right amount overnight, grocery spend would drop 10-20%.

But since it's 16% on these drugs, and figure since they are Losing Weight (not maintaining), safe to say those 16% of Americans are eating 20-30% less... 20-30% times 16% = 3-5% decrease in spend.

So it tracks, roughly. And we are not at the bottom yet.

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> The data I have seen says the average American eats 400-700 excess daily calories, and 3600 daily calories total. That means 10-20% excess per person. If everyone started eating the right amount overnight, grocery spend would drop 10-20%.

You're falsely assuming a 1:1 ratio between calories and cost. Unfortunately the big problem with ultra processed food is that calorie rich but nutrient deficient food is way cheaper than the less processed foods. Cutting out the cheapest items is going to reduce spending less.

>You're falsely assuming a 1:1 ratio between calories and cost

Not falsely. Back of the envelope. If you want to improve the model go right ahead, but I was upfront with its limitations.

I got some similar responses on my post above. HN discussion quality is really suffering recently. Wondering how many LLMs are involved here at this point.

> calorie rich but nutrient deficient food is way cheaper than the less processed foods

I hear this a lot but I really don't see good evidence for it. And people keep peddling stereotypes about "fast food" consumption after QSRs saw much larger price increases than grocery stores. For that matter, the UPFs are where I see people most commonly reach for overpriced name brands over the generics.

> jjk166: You're falsely assuming a 1:1 ratio between calories and cost Give the guy some credit... No, clearly CGMthrowaway is not assuming that at all, it's purposly left out. The first sentence mentions "back of the envelope math" and makes it clear it's a rough order-of-magnitude estimate. Also it's in response to a statement about "wondering how you could get such a high impact overall". Also, also, the last sentence is "So it tracks, roughly. And we are not at the bottom yet."

It's perfectly fine for people to do rough estimates to understand a situation, especially in informal discussions. It not a dissertation for a Ph.D. or formal position paper.

>> calorie rich but nutrient deficient food is way cheaper than the less processed foods

How much is a bag of Doritos? Compare it with a bag of white rice, dry lentils, raw potatoes - processed is often more expensive.

The decrease in spend was at the household level, not aggregate, so it’s a 5% decrease across 16% of households, or a bit less than 1% overall.

The overall weight loss seems to be because the spending decreases most heavily in calorie dense foods like savory snacks; yogurt and fresh fruit spending goes up a bit.

> the average American eats 400-700 excess daily calories

This can't possibly be true. A caloric surplus of 500cal/day adds a pound of weight per week. That'd mean in a decade of life the _average_ American would add an additional 260 pounds. In 4 decades Americans would add half a ton to their waistline, on average.

That'd mean at then end of their life the average American would die weighing over 2 tons

The question is how you calculate or define excess. For one, excess calories aren't 100% stored as fat. We're not that efficient.

Additionally the fatter you are the more calories you use at rest. So there's a point where if you consistently eat too much you'll stop gaining weight.

The biggest source of error here will be the calories in the garbage bin though. I wouldn't be surprised if a lot of this is stored in the waste disposal, not the waist disposal.

If I throw away 500 calories of food, I'm not eating an excess 500 calories. Let's not engage in equivocation

If you don't read the main part of my reply, why do you even reply with snarky nastiness.

Assuming a steady surplus of 500, and considering that a kg of human fat is roughly 8000kcal, it will take two weeks to gain a kilo. But a larger person consumes more to simply stay alive so the curve flattens out once a certain mass is reached.

Excess means above what your metabolism consumes. If I'm 200 pounds and my metabolism consumes 3200 calories per day, eating 3200 calories per day isn't 500 calories in excess. Same as if I'm 600 pounds and 4000 calorie metabolism. It isn't excess unless its excess.

Hm, good point

In excess or a normal body's caloric need, not in excess of what you need to maintain your current weight. The latter would lead to infinite growth.

Once you're 140kg, a sedentary lifestyle requires you to take something like 800 more calories as the same person with the same lifestyle at 70kg, to each maintain your weight.

So excess eating of 500 calories over what a normal bodyweight (say 70kg) needs to maintain, leads to fat people (say 110kg) who at some point stop gaining weight and stay at that fat level (of say 110kg).

> That means 10-20% excess per person. If everyone started eating the right amount overnight, grocery spend would drop 10-20%

I doubt that $ spend on the top end of caloric intake scales linearly with # of calories because of high caloric density foods.

If I spend $500 a month on groceries, lets say I need $400 to keep me alive and hygienic and the last $100 are going to be the candy and sodas that make me fat. So to give an example, reducing the caloric intake by 50% could be achieved by reducing spend by only 5% if there's very caloric foods making me fat.

Also need to account for restaurant spending.

> But since it's 16% on these drugs, and figure since they are Losing Weight (not maintaining)

I would not assume this. Most people remain on GLP-1 agonists after they reach their goal weight, as without it cravings return and weight starts coming back on. I would guess a substantial fraction of people on the drugs are on a maintenance dose

These calorie numbers don't make much sense to me. The typical recommendation for how much a man should eat is 2000-2800 Cal/day, and for the average woman that is 1600-2200 Cal/day, depending on age and exercise levels [0]. So if it were true that the average American ate 3600 Cal/day, they would be eating 800-2000 excess Cal, not 400-700.

Even if we assumed that average food cost/Cal is a meaningful concept, the reduction would be much higher.

[0] https://www.ummhealth.org/health-library/eating-the-right-nu...

You're right I seem to be referencing bad data, and the excess is probably more like 10-50 cals/day.

Whatever the figures are, what's interesting to me is the growing secular impact on an entire sector of the economy (the most stable and inelastic sector). If eating right means spending 5% less, extrapolating that across the entire sector, not just for the 16% using GLPs today, could be catastrophic

I suspect ultimately though supply will meet demand and prices may even rise for the food people are still eating

I'm not sure how this math checks out.

1lb of fat is roughly 3500 calories. Given 500 calories a day of excess, that would lead to 1lb of fat gain per week. 52 pound average gain per year?

As you gain weight, your base metabolic rate also increases. Having fat means you inherently burn more calories, even if you don’t exercise any more.

Take one person, say they eat 2000 calories to maintain bodyweight. If they start eating 2500 calories a day, they won’t gain 1lb of fat a week forever. As they gain fat, their body naturally burns more calories due to the increased body weight, and eventually a stable weight (higher than their original weight) will be reached.

So yeah if you’re eating 500 calories above your metabolic weight, you’ll theoretically gain weight forever. But in this case your metabolic rate is rising over time, so you would be eating more and more calories per day.

Fat does not raise your metabolism by a lot (relatively), and tiny changes in diet lead to massive swings in the equilibrium implied by basal metabolic rate formulas. In fact, some formulas do not include weight due to body fat. If you think about it, that fact touches on the idea that your natural weight is being maintained by another body system, one related to GLP-1.

By the way... if humans had to count calories to not accidentally starve or die from overeating, we would not have made it long enough as a species to invent a scientific way to do that. Even the diets of obese or overweight individuals are being naturally regulated, because anyone could physically eat even more.

The potential for overeating chronically has not been possible for most people, in most societies, throughout most of human history. Our current caloric abundance being available to literally everyone in Western society is something unique to the past century.

If you eat 1% fewer calories than you burn every day you will die. You will also die if you eat 1% more calories than you burn every day. Is it possible, really, to suggest that the availability of calories was 100% of the daily requirement of our ancestors, and not 99%, or 101%? That is a level of accident that exceeds belief.

It is incredible to think this precise balance could be maintained by anything other than a closed loop of biological control. How would the wheat on a medieval farm know how much to grow each season? If it was off by 1% consistently, everyone would have died... unless they had a mechanism for satiation.

How do you think our microbial ancestors maintained internal salinity, through the limited availability of salt in the ancient ocean?

> unless they had a mechanism for satiation

It ends up being the opposite. Rather than the body having a satiation response, it controls the metabolism.

If you've ever fasted, you've experienced this. You just don't have the energy to do much other than sit around when you are hungry.

Ancient societies realized this, it's why they'd give out calorie dense meals to their farm labor. For a serf in England, harvest time was often met with a very calorie dense meal. For roman soldiers, they had a diet of meats and cheeses.

I'd also point out that you don't need to have exactly 100% daily calorie intake. You can go a week with just 99% and catch up with 101% the next week just fine.

You will also die if you eat precisely the amount of calories you burn every day.

There exists something called a "feedback loop", something common in biology. You would probably find it interesting, you should look it up.

Basically, it means that if you try to chronically eat, say, 1% more calories than are burned, your body will try to burn more calories to compensate.

I'm not sure I grasp the rest of your comment, could you try again to explain? The wheat farm your ancestors worked did not provide the excess of cheap calories available to the present day American.

That is the intended conclusion of my post, that body fat is obviously regulated biologically, and suggestions that changes in obesity rates are due to the increased availability of food (implying that it was regulated by some sort of precise cycle of starvation in the past) or individual choices (implying that most people are measuring portions and keeping a running tally) are in conflict with that.

You haven't made that point and I disagree with your conclusion.

Your error is claiming some "precise cycle of starvation" is necessary to explain obesity via increased caloric availability.

In reality there were times of excess and times of shortages far more often in past times. In times where there were plenty of items that didn't last you over consumed. By late winter you were getting lean.

>If it was off by 1% consistently, everyone would have died...

You do realize that starvation was a massive killer in the past. Everyone didn't die, but the young, the old, and the weak sure did.

It's not necessarily about BMR - if you maintain a similar activity level as you gain weight, you consume more active calories as well, in almost every activity, particularly the most common ones such as walking.

This hits on something that seems to get lost in most of these "obese people are lazy fat slobs" circle jerks. A typical American gains 1 or 2 pounds per year as they age. This is not a candy problem, or a binge eating problem, this is way more subtle than that.

More subtle as in still not a healthy diet with exercise?

Let's take a pound of fat as 3500 calories. To gain one pound in a year is an average of 9.59 excess calories per day. Or about 0.5% of the typical total daily intake.

Yeah, managing a system within 0.5% is subtle.

Especially when biologically and psychologically the pressure is towards over consuming rather than under. If you consistently eat a deficit you will very obviously feel hungry. If you consistently eat a small excess the effects that would lead you to regulate are much more... subtle.

10 calories a day is like the BMR difference between 20 and 30.

Meanwhile, tracking consumption involves error bars that span a factor of 2. Go figure out how many calories are in an avocado. Is that per gram figure amortized for the weight of the pit, or is this just for the flesh?

Counting calories precisely was invented by the processed food industry.

Judging from the downvotes my observation got, you're not the only person who skipped math class. I couldn't say it any better than the comment below this one that already replied to you. 10 calories a day, expressed in candy, is two M&Ms.

There is no direct correlation between dollars and calories though. I could spend 10 dollars on 400 calories of strawberries or 10 dollars on 4000 calories worth of cheetos. So theres no way to do that kind of math on this, really

> If everyone started eating the right amount overnight, grocery spend would drop 10-20%

Probably not. Americans (households, grocery stores, and restaurants) throw away an insane amount of food.

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