The Personal Blog of Stephen Sekula

Surprise, surprise: it’s the physics diet, stupid.

The NY Times reported that the results of an extensive study comparing diets found that it was calorie reduction, independent of the means by which calories were reduced, that caused weight loss [1]. Surprise, surprise. As cranky Maryland physicist Bob Park has put it many times before [2],

Eighty-five percent of Americans list weight loss as their top goal, but studies find we are going the other way. So Secretary of Agriculture Dan Glickman invited authors of the most popular diet plans to Washington to debate nutrition. At one extreme there was Dr. Dean Ornish pushing his high-carbohydrate diet, and at the other Dr. Atkins, the current number one best-selling author, urging people to eat the hamburger patty and the cheese and throw away the bun. Atkins, who didn’t look exactly svelte, took a postprandial nap during the proceedings. Since all of these best-selling authors have become millionaires, WN decided to offer the “physics plan”: burn more calories than you consume.

Physics has always offered a simple recipe for weight loss: if energy input is less than energy output, the body will plunder its energy reserves (fat) to make up the difference until eventually equilibrium is achieved. Physics doesn’t care how you achieve that, it doesn’t care what a best-selling medical guru (or snake-oil salesman) is pitching, and it doesn’t care whether you eat less carbs and more protein. Just cut a fixed number of calories from your diet. In fact, if you cut 500 calories from your typical daily diet and set that as your new typical intake, you’d lose 1 pound per week until equilibrium is achieved [3].

Energy is energy. Whether it’s in a quark, in a photon, in a candy bar, or in a cracker, energy is stored and transformed from one form to another. The secret to losing more of your own stored energy is to simply stop providing a steady supply of new energy to maintain the store.

Nice to see somebody finally taking a shot at separating fact from fad.

[1] http://www.nytimes.com/2009/02/26/health/nutrition/26diet.html?ref=us

[2] http://bobpark.physics.umd.edu/WN00/wn022500.html

[3] http://www.mayoclinic.com/health/calories/WT00011