Mindsets and Milkshakes

by Michelle Chang

A Slice of Research from the Stanford Mind and Body Lab

If you want to maintain or lose weight, you might want to think twice about simply going for healthy, low-calorie meals.

That is, according to what Dr. Alia Crum, principal investigator of the Stanford Mind and Body Lab, has learned from her research. An assistant professor of psychology, Dr. Crum studies how subjective mindsets alter the way we perceive objective reality. “Personally, I struggled with my weight and eating the right foods in order to function as a Division I athlete during my undergraduate days at Harvard,” she explained. “That drew me to the problems I’m researching as a psychologist today.”

Part of Dr. Crum’s answer to her struggle as a varsity ice hockey player was inspired by the placebo effect. As an undergraduate student, Dr. Crum completed a literature review on placebos, typically known as the “sugar pills”, which are often used as the control condition in clinical trials of active drugs. The broader definition of the placebo effect encompasses the effects not of active drugs but of people’s beliefs about those drugs. Crum found that, even when the drug outperformed the placebo, the placebo accounted for much of the medication’s efficacy.

“I was just really blown away by how robust the placebo response is and how important it is in producing the effect of medications. What was most powerful for me is how our beliefs about something could change our body’s response,” Dr. Crum says. “The question then occurred to me: how much is the effect of the foods we choose due to what is in the foods – the nutrients, the calories, the fat – and how much of that effect is perhaps due to our beliefs about those foods?”

Refuting “Calories In, Calories Out”

While completing her PhD in Clinical Psychology, Dr. Crum revisited this question with an experimental approach. Believing that they were participating in a shake-tasting study, 46 participants came into the lab twice. Both times, they consumed the same 380-calorie milkshake, but it was presented as a high fat, 620-calorie “indulgent” shake one time and as a low fat, 140-calorie “sensible” shake the other time. Her team then took blood samples to measure participants’ ghrelin levels before and after consumption of the shake. The gut peptide ghrelin measures how “hungry” someone feels: before eating, ghrelin levels increase to induce appetite, and after eating, ghrelin levels lower to reduce appetite, making someone feel satiated.

The results demonstrated that when participants believed that they were drinking a healthier, “sensible” shake, their ghrelin levels remained mostly flat before and after consumption–meaning that they did not feel satiated. However, when they believed that they were drinking an “indulgent” shake, their ghrelin levels dropped about three-fold after consumption–meaning that they were more physiologically satiated.

Even though the contents of both milkshakes were exactly the same, what made a difference in how hungry participants felt was participants’ mindsets about food. Indeed, the belief that one is eating healthily may actually be counterproductive to those trying to maintain or lose weight, as this belief can increase appetite and slow metabolism.

“The results were paradigm-shifting,” Dr. Crum recalls. “The results challenged our traditional assumption that metabolic or weight maintenance is about calories in, calories out. It suggests that what matters is not just what we eat, but also what we think about what we eat.”

The notion that the mind alone can change our body’s physiological responses sounds like the stuff of “mind control” science fiction novels. However, the results of Dr. Crum’s study came at a critical time when medicine was shifting its focus from infectious diseases to chronic diseases, and when treatments were shifting from pills to behavioral modifications.

Inside a team discussion at the Stanford Mind and Body Lab.

“We’ve been trying for a long time to combat obesity and health-related issues on the one hand and eating disorders such as anorexia and bulimia on the other hand. In many ways, both of those approaches were failing. The practical implications of this finding, that the mindset of sensibility is counterproductive, helps provide a reason for why our traditional approaches to obesity are failing and why this war with food keeps perpetuating these issues,” Dr. Crum explains.

Still, the study is not an end-all; there are still limits to how the results should be taken.

Professor Alia Crum brings a new perspective on food to the table.

The question that comes up is how much does the mindset matter? We’re still understanding that we can shift our physiological responses according to our mindsets–but not so much so that we become divorced from reality. However, we’re not licensing people to stop paying attention to their physiological health or the objective nutrients of food,” Dr. Crum warns.

Cultural Notions of Healthy Eating

More broadly, Dr. Crum is exploring how mindsets about healthy eating are portrayed, not in a tightly controlled laboratory study, but in general American culture. Her team is currently investigating the differences in how restaurants describe and market their “healthy options” and regular options.

Other cultures may offer some insight on what a healthy mentality around food could look like. Take, for example, the French paradox: French foods tend to be high-fat, with lots of cream, wine, and carbs, yet the French do not have nearly the rate of obesity that Americans have.

Dr. Crum proposes that “part of this paradox might be driven by the French mindset around food as an experience to make time for. When they eat, they sit down and have a mindset of indulgence. This has a more adaptive physiological response, rather than the war with food that we have in this country.”

Personal Applications of Research

On a personal level, Dr. Crum is encouraged by the impact that her milkshake study had on changing her own approach to eating.

“I still eat healthy wherever I can, but I focus more on feeling a sense of indulgence when I’m eating. Even if I’m having a salad, I think about all its nutrients and all that went into growing these vegetables, so that I’m indulging in my salad,” Dr. Crum describes. “My approach when choosing foods is more about ‘What can I eat that is going to make me feel good?’ rather than constantly restraining my desires and settling for the lightest or lowest calorie option.”

Where does Dr. Crum want to go with all of this? Her team is now partnering with restaurants and organizations to shift their labeling and marketing of healthy foods, employing mindset insights to improve the health of their constituents.

“What I’m trying to do now is help people reach higher levels of health and flourishing through their own agency. That’s what I’m really passionate about. The running joke is that psychological research is ME-search,” Dr. Crum laughed. “At the end of the day, our relationship with food is a very deeply human experience.”

Photo credits, in order of appearance: Flickr/Unskinny Boppy (milkshake); Flickr/Panu Tangchalermkul (nutrition facts); Michelle Chang (lab meeting); Alia Crum (Crum giving a presentation); Flickr/Jeremy Keith (salad).