400 extra calories over a year (assuming 3500 calories = 1 pound) is an extra 41.7 pounds per year.
In reality, you’ll stop gaining weight at some point if you increase your caloric intake once and never change it again, because your energy expenditure will rise.
But even taking that into account, it does seem to me that 456 extra kcal per day is way too much.
Here’s an illustrative calculation. Herman Pontzer has the following equations relating body weight to total daily energy expenditure in his book (figure 3.4):
TDEE={766⋅ln(weight in kg)−1582,for women1105⋅ln(weight in kg)−2613,for men
The average woman in the US weighed 65.5 kg in the 1970s, and 78 kg in the 2010s, so this predicts a TDEE increase of only 134 kcal for women. For men, the figure is 160 kcal. Those numbers are about a third of 456 kcal. So yes, a 456 kcal in average daily energy intake would be a jaw-dropping increase.
Of course, this 456 kcal number is based on self-report data, so it’s not likely to be that accurate. Stephan Guyenet mentions a better estimate on The Hungry Brain based on food disappearance data from the USDA, which is only 218 kcal/day, much closer to my estimates of how much TDEE has changed.
I agree with Eliezer et al. that CICO by itself cannot explain the obesity epidemic, but “a 456 kcal increase is not that much” is a bizarre argument.
Since this seems like a question at the center of this whole thing, I just wanted to double check using other sources. Using [this](https://www.omnicalculator.com/health/tdee) calculator with the “little/no exercise” setting, I see
Female; 36; 5′4″
Weight: 65.5 kg → 78 kg
TDEE: 1596 → 1746
Diff: 150 kcal/d
If we set it to “moderate exercise”, the gap increases to 194 kcal/d
In reality, you’ll stop gaining weight at some point if you increase your caloric intake once and never change it again, because your energy expenditure will rise.
But even taking that into account, it does seem to me that 456 extra kcal per day is way too much.
Here’s an illustrative calculation. Herman Pontzer has the following equations relating body weight to total daily energy expenditure in his book (figure 3.4):
TDEE={766⋅ln(weight in kg)−1582,for women1105⋅ln(weight in kg)−2613,for men
The average woman in the US weighed 65.5 kg in the 1970s, and 78 kg in the 2010s, so this predicts a TDEE increase of only 134 kcal for women. For men, the figure is 160 kcal. Those numbers are about a third of 456 kcal. So yes, a 456 kcal in average daily energy intake would be a jaw-dropping increase.
Of course, this 456 kcal number is based on self-report data, so it’s not likely to be that accurate. Stephan Guyenet mentions a better estimate on The Hungry Brain based on food disappearance data from the USDA, which is only 218 kcal/day, much closer to my estimates of how much TDEE has changed.
I agree with Eliezer et al. that CICO by itself cannot explain the obesity epidemic, but “a 456 kcal increase is not that much” is a bizarre argument.
Since this seems like a question at the center of this whole thing, I just wanted to double check using other sources. Using [this](https://www.omnicalculator.com/health/tdee) calculator with the “little/no exercise” setting, I see
Female; 36; 5′4″
Weight: 65.5 kg → 78 kg
TDEE: 1596 → 1746
Diff: 150 kcal/d
If we set it to “moderate exercise”, the gap increases to 194 kcal/d
[This](https://www.niddk.nih.gov/bwp) calculator yields similar results
So, pretty much in line with your conclusion.