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Comment by falcolas | Hacker News Reader

How many calories are you taking in? The answer is: It depends. There's a huge number of factors involved in simply identifying the number of calories present in the food we eat. Some studies show as much as a 20% difference in what was on the label and the actual caloric content. And that doesn't even account for how many calories are actually absorbed by the body - a value which has even more confounding factors.

How many calories are you expending? The answer is: It depends. How (warm|cold) is it? What's your average body temperature? How much clothing do you wear? What's your genetic makeup? Doing a lot of thinking? What's your current exercise regimen? Is your body in state X where it burns (more|less) calories than state Y? Are you sick?

Calories in and calories out sounds good on paper and seem obvious to an engineers mind, but if you can't tell how many calories are involved on each side of the equation, it's a meaningless measure.

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How many calories are you taking in per day to 0.1 kcal? The answer is if you want to lose weight it doesn't matter. You just need to average a deficit over time.

We are not sending a rocket to the moon here. Just because something cannot be measured exactly doesn't mean it's worthless to measure.

> The answer is if you want to lose weight it doesn't matter. You just need to average a deficit over time.

If this were the case, Weight Watchers (which is at its core a calorie limiting system) should have a near 100% success rate. It doesn't. A casual perusal of Google shows closer to a 50% success rate for a 5% body weight change.

I can't think of many medical treatments where we go "yeah, a coin toss level of success is good enough for me."

As for the accuracy of the measurements - it does matter. Healthy weight loss rates are, mathematically, in the 10% calorie reduction range. That's less than the error rate for the caloric labeling of many foods.

I don't think you can draw meaningful conclusions from a self-enforced system like Weight Watchers either though. Self reporting particularly when it comes to anything diet related is going to be heavily skewed. There will always be social pressures within a group like that to over report exercise and under report intake.

If you can't trust the results of a self-selected group of individuals who are paying a good chunk of cash for the express purpose of loosing weight... who the hell can you trust?

Generally speaking you're absolutely right, but with diet the social pressures are significant enough to compromise analysis even if the group is paying for it. There have been quite a few studies on the topic, e.g.: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.103...

>If this were the case, Weight Watchers (which is at its core a calorie limiting system) should have a near 100% success rate. It doesn't. A casual perusal of Google shows closer to a 50% success rate for a 5% body weight change.

First off - that's an astonishing success rate against a backdrop of an article saying, literally, surgery is the only reliable option.

Second off - You're assuming 100% compliance. I know people with personal trainers who are gaining weight because they don't stick to the program. I halfheartedly went through a weightlifting routine for years and got nowhere because I never really stuck to the program. 100% compliance in the field of weight loss is just not going to happen.

>if you can't tell how many calories are involved on each side of the equation, it's a meaningless measure.

Incorrect. It's an imprecise measure. You said "Some studies show as much as a 20% difference in what was on the label and the actual caloric content". So then the labels are accurate within a 20% margin of error at worst.

Sounds like a pedantic little nag but then again

- "Star Spangled Blizzard - Mini" - 430 calories

- 1 serving of broccoli (1/2 cup, cooked) - 25 calories

A 50% margin of error would be fine given some of the choices out there. With that said, you usually don't pick between a dq blizzard or broccoli. More reasonable comparisons would be a blizzard vs water (0 cal) or broccoli vs french fries (regular size - 290 cal).

In a nutshell: if a thermostat's off by up to 10 degrees it can still ballpark whether the temperature's livable.

https://www.dairyqueen.com/us-en/Company/Nutrition/Treats/

https://www.livestrong.com/article/402398-what-is-a-serving-...

This is, almost literally, a comparison between apples and orange candy. The two are so incomparable that it's meaningless.

Now then, if you were comparing a Starbuck's chocolate muffin and a Blizzard as a treat to fit into your diet without blowing it - could you?

if you were comparing a Starbuck's chocolate muffin and a Blizzard as a treat to fit into your diet without blowing it - could you?

If I'm having a "treat" then I'm already blowing my diet; regardless of if the number fits within a calorie goal.

A calorie budget is a bit like a financial budget. Just because I have allocated a point up to which I can "spend" each day, the long-term goals are a force to minimize day-to-day spend even within that allocation.

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