That's the question asked in a great video by Evan Fraser at the University of Guelph. I don't agree with all of this solutions but he provides some good food for thought on an important question that often gets overlooked in food discussions.
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Does 1 lb = 3500kcal?
Researchers studying the effect of various food policies on changes in weight often use the simple saying that a change of 3500 kcal via diet or exercise results in a 1 lb change in weight (it is a claim we repeated in our paper in the Journal of Health Economics, which studied the efficacy of fat taxes).
I ran across this interesting post by a Mike Gibney, a public health and nutrition expert, who points out some problems with the 1 lb = 3500 kcal calculation. Here's what he has to say:
Firstly, a 1lb weight loss will not be 100% fat but will also involve the loss of some lean tissue (muscle and protein elements of adipose tissue and its metabolism). Whereas fat has an energy value of 9 kcal/g, lean tissue has a value of 4 kcal/g. The exact ratio of the loss of lean and fat in weight reduction depends largely on the level of fat in the body at the outset.
and:
The second criticism of this rule is that it ignores time. If you shed 3,500kcal per week every week, that would differ from a deficit of 3,500 kcal per month every month. The former leads to a daily deficit of 500 kcal while the latter is just 117 kcal.
and:
Thirdly, the 3,500 kcal rule assumes complete linearity – in other words the rule equally applies, pound after pound of weight loss. We saw above that progressive weight loss will progressively increase the % of that weight loss as lean tissue but more importantly, the 3,500kcal rule ignores a major adaptation in energy expenditure
and on this topic, he concludes:
Clearly, the continued use of the 3,500 kcal rule in predicting weight loss should cease and the recommendations of the consensus statement of the ASN and ILSI should apply: “Every permanent 10 kcal change in energy intake per day will lead to an eventual weight change of 1lb when the body reaches a new steady state. It will take nearly a year to achieve 50% and about 3 years to achieve 95%”.
Finally, I'll point out the importance of taking into account these kinds of issues when calculating the effects of fat taxes. He says that according to one study, a 20% soda tax would lead to;
a reduction of energy intake of 34-47 kcal per day for adults. Using the 3,500 kcal rule, an average weight loss of 1.60kg would be predicted for year 1 rising to 8kg in year 5 and to 16kg in year 10. However, when the dynamic mathematical model is used, the corresponding figures for years 1, 5 and 10 are, respectively, 0.97, 1.78 and 1.84 kg loss. The % of US citizens that are over-weight is predicted to fall from existing levels of 66.9% over-weight to 51.5% over-weight in 5 years time using the 3,500 kcal rate but using the dynamic mathematical model, the 5-year figure for the over-weight population in the US would be just 62.3%.
The Fat Tax that Wasn't
A while back Denmark passed a law to implement one of the first comprehensive "fat taxes." A year after its implementation, it looks like they've changed their mind.
One of the biggest drivers of the reversal was apparently public opinion, not to mention the negative economic impacts.
I am often amazed at how easy many public health professions believe it is to change weight and corral bad behavior simply by just slapping a tax on things they don't like. Just today, the folks over at Freakonomics discuss a recent conference where fat taxes were thought a really good idea (I've been a many of these kinds of meetings too).
We economists often come across as uncaring , negative Nellies when we point out that such taxes often have very little effect on weight, have unintended consequences (as Denmark just realized), and are regressive (meaning that food taxes hit the poor the hardest).
But, at the end of the day, who is more caring? The folks pushing for costly taxes that wont materially change weight and health or those of us trying to prevent bad policies from affecting those who can least afford to pay the effects?
How Big Food Responds to Big Government
People who advocate for bans on large sodas, taxes on sugar and fat, and mandatory calorie labels in restaurants often forget that food companies don't just sit idly by and follow the intentions of the policy makers. Rather, firms (and even consumers) strategically respond to a new food environment - often in unanticipated ways.
On that note, here is a paper that just appeared in the European Review of Agricultural Economics by four French researchers.
They argue that:
. . . it is important to take into account the fact that food consumption decisions involve many dimensions related to price, taste, product convenience, health issues, etc. A consumer has to manage a trade-off between several product characteristics. Similarly, the firms have to deal with these multiple dimensions of food consumption in order to compete on a market in which the nutritional quality is just one of many criteria considered by consumers. The analysis of the economic effects of nutritional regulation must not neglect all of these dimensions as changes in the other (nonnutritional) product characteristics may be a response to nutritional policies which affects the welfare and the economic efficiency of nutritional regulation.
and
our results show that nutritional regulations may induce changes in consumers’ decisions and the product quality choices by firms, but they may also affect the competitive game. In an imperfect competition setting, firms react not only by adjusting price and product quality, but also by modifying the product variety available on the market and hence the level of substitutability between food products. This situation can lead to adverse effects from a public health perspective. Indeed, we show that if the tax rate is not well adjusted according to the quality threshold imposed to avoid taxation, it is possible to observe economic distortions that are not compensated by increased health benefits.
The Presidental Election and Food Policy
Over at Reason.com, Balyen Linnekin wrote a column last week where he shared his perspectives on the
ten important federal food-policy issues the presidential candidates should be discussing but have ignored until now.
Yesterday, he put up another post:
my goal for this week's follow-up column would be to go beyond my own ideas by presenting one idea each from 10 leading food scholars, attorneys, authors, advocates, and others about important food-policy issues they'd like to see discussed in the presidential campaign and implemented in the future.
Here were my thoughts, which Balyen included in his post (I'm number 6).
The government-funded school lunch program is a bureaucratic nightmare that attempts to do too much: prop up agricultural prices, provide calories to poor under-nourished children, slim the waistlines of the obese, and it forces schools to follow complex rules subject to annual audit. The government subsidizes the price of foods sold from selected distributors and it re-reimburses schools for certain types of students. Why not take these same funds and provide block-grants to schools and let local school boards make their own decisions outside the complex government formula system? We allow charter schools. Why not charter lunchrooms?
Number 7 was also on school lunches. Check out the other 8 ideas.