The Trouble with Most Psychological Approaches to Weight Loss: They Assume the Biology is Obvious, When It Isn't

Psychological approaches to weight loss send people to battle hunger and food cravings head on. But a large component of hunger and food cravings is governed by biological forces that can be sidestepped and don’t need to be fought at all. In “4 Propositions on Weight Loss” I lay out the theory that there are certain foods that generate powerful biological hunger and food cravings: sugar, bread, rice and potatoes, plus others that can be determined by personal experimentation. Avoid those foods, and then you will only have to face narrowly psychological desires for food. Eat sugar, bread, rice and potatoes, and you will face strong physiological cravings to eat more than is good for you. Indeed, avoid sugar, bread, rice and potatoes and you will be well on your way to facing surprisingly little hunger even when you eat nothing at all, because your body will be able to switch over relatively easily to burning your own fat stores.

Going off sugar, bread, rice and potatoes may seem superhuman, but it isn’t when you immediately substitute other treats such as nuts, manchego cheese or cherries and cream (or cherries and canned coconut milk). Also, eating a giant salad each day before you let yourself eat anything else (other than nuts and salad ingredients) can do a lot to reduce temptation. I give practical tips in “Letting Go of Sugar” and “Our Delusions about 'Healthy' Snacks—Nuts to That.”

A lot of the idea that dietary fat is bad for weight loss comes from people combining dietary fat with sugar, as I discuss in “Does Sugar Make Dietary Fat Less OK?” If you cut out sugar and other troublesome foods like bread, rice and potatoes, then dietary fat will make you feel full quite fast. Indeed, big doses of fatty foods like avocados and olive oil in a salad are some of the healthiest things you can eat, and can do a lot to keep you satisfied long after your meal.

In the contest for best simple message to aid weight loss and health, I’d bet on “Sugar is bad” against “Reduce calories” any day. As a matter of public health, the message “Reduce calories” has only led to rising obesity. It is true that the message “Sugar is bad” is out there at some level, but it lacks the punch it needs without comparisons like

  • Sugar is much, much, worse than butter or cream or oil.

  • The worst thing about bacon is the sugar added to the bacon.

  • Don’t worry about calories, just cut out all sugar.

To go further, I would add these:

  • In bread and butter, it’s the bread that’s unhealthy, not the butter.

  • In fried rice, it is the rice that is unhealthy, not the oil the rice is fried in.

  • The worst thing about french fries is that they’re made of potatoes, not the oil they’re cooked in.

  • In a hamburger, it is the bun that is the unhealthiest part.

(Update: @sudeepj21 points out that when vegetable oil high in polyunsaturated fat is cooked at high temperatures, all sorts of bad chemicals are created. So certain oils, at high temperatures, can indeed become quite unhealthy. Summing up, @sudeepj21 writes: “So French Fries just might be the mother of all bad ideas.. (unless fried in butter..) Carbs + PUFA oxidized at high temperature for a long time.”)

The article I flag at the top of this post, Bee Wilson’s September 6, 2018 Wall Street Journal article “No, A Salad Doesn’t Make that Burger Healthier,” raises the question of whether being combined with healthy food can reduce the harm of unhealthy food. She stresses one part of the answer: a token amount of healthy food can’t redeem unhealthy food. The next part of the answer is that nothing can redeem sugar, bread or potatoes. Jason Fung, in The Obesity Code (a book I highlight in “Obesity Is Always and Everywhere an Insulin Phenomenon” and Five Books That Have Changed My Life) suggests that acidic things such as vinegar or Japanese pickled vegetables might help redeem white rice. Being full-fat helps redeem milk: I take a dimmer view of milk overall in “Is Milk OK?” (I have more to say on that in the future) but if the choice is between whole milk and skim milk, the message of Whole Milk Is Healthy; Skim Milk Less So is still helpful. Fiber can help slow down the insulin response to many things.

Thinking about things in terms of calories makes it seem obvious that adding healthy food can’t make unhealthy food less unhealthy, but thinking in terms of insulin responses can focus attention on the idea that adding oil or fiber or vinegar might help slow down the insulin kick of a not-so-healthy food. But sugar is so bad, I argue in “Does Sugar Make Dietary Fat Less OK?” that the interaction goes the other way: sugar makes dietary fat worse, which means that dietary fat makes sugar worse. With bread and potatoes, I am have less of a sense. I would start from the assumption that the harm of the bread in a sandwich is simply a big subtraction from whatever good there is in what is inside the sandwich.

That question of interactions between good and bad things in “No, A Salad Doesn’t Make that Burger Healthier” is a good one, but I am turned off by two undefended assumptions in the article: (1) that thinking about calories is helpful (see “Forget Calorie Counting; It's the Insulin Index, Stupid,” “Nina Teicholz on the Bankruptcy of Counting Calories” and “Mass In/Mass Out: A Satire of Calories In/Calories Out”); (2) the psychologizing of the problem of weight loss. To me, understanding the biology of hunger—in particular the role of sugar, bread rice and potatoes, and how done right, fasting (drinking water, but not eating food) doesn’t necessarily lead to a lot of hunger—is a much bigger deal than understanding tidbits of psychology about calories like this:

Dr. Chernev found that if you ask people to estimate the calories in a hamburger, they will usually estimate more calories for a hamburger by itself than for a hamburger with a few sticks of celery or a carrot salad on the side. Many of the participants imagined that a burger by itself was around 600 calories, whereas they reckoned that a burger plus celery was more like 500 calories.

Don't miss these other posts on diet and health and on fighting obesity:

Also see the last section of "Five Books That Have Changed My Life" and the podcast "Miles Kimball Explains to Tracy Alloway and Joe Weisenthal Why Losing Weight Is Like Defeating Inflation." If you want to know how I got interested in diet and health and fighting obesity and a little more about my own experience with weight gain and weight loss, see my post "A Barycentric Autobiography."