As a follow up to Charlene’s post on eating hyper-palatable foods during eating disorder treatment , I asked Liz–SEDs’ resident expert on animal behaviour, particularly in relation to binge eating and drug addiction–to look at some of the studies that Julie O’Toole mentioned as evidence for Kartini Clinic’s guidelines of avoiding hyper-palatable foods for the first year of eating disorder recovery. If you missed Dr. O’Toole’s post, please do take a look. Here’s the main conversation that led to this post:
In the comments, I asked Dr. O’Toole,
I agree that eating cheetos and sugar-y drinks is ubiquitous but not exactly healthy, and I too question many versions of “normal eating” that people promote (and *everyone* has an opinion), but I wonder — if there’s any evidence for not allowing hyper-palatable foods to patients for a year? And what does the Kartini Clinic consider to be hyper-palatable? Why not just allow it in small portions and occasionally?
Dr. O’Toole’s response:
I am, of course, painfully aware that most places do not temporarily restrict palatable or hyper-palatable foods, but let me see if I can assure of the evidence base used for this recommendation.
First there is the Minnesota Semi Starvation Study (MSSS): In his two volume treatise on human starvation, Ancel Keys discussed the consequences of “ad lib”referring with access to calorie dense, sweet, high fat foods. He discussed cases of bingeing that resulted from this practice and the resultant weight gain. Among the many, many discussions throughout this well known and massive work, Keys says (page 127) “The tendency toward overeating following a period of reduced food intake has been noted repeatedly under conditions of natural starvation when food suddenly becomes available again in large quantities. The experiences of semi starved explorers document particularly well the surprising lack of self-control even in the face of clear knowledge that the overindulgence will certainly result in discomfort and may have fatal consequences….”
The Biology of Human Starvation Vol. 1 University of Minnesota Press 1950 (page 127) Ancel Keys et al. Please do check it out and especially the graph illustrating the weight curve for when the “patients” were re-feed on a plan (v.s. “ad lib”), and then once they were given access to ad lib feeding of anything they wanted. This graph shows that eating (and weight) normalized after about 1 ½ years—although, once ad lib feeding of anything they wanted was introduced they gained weight way past their own norm; it just took about 1 ½ years for all that to normalize and the weight to re-adjust.
In the words of one “survivor” of this study: “we got fat”. Why is it necessary to let that happen? Take a look, I’d be interested in your interpretation.
The term hyper palatable food comes from the research arena using animal models of eating behaviors and refers to the high calorie/high fat/sweet dessert and snack items very prevalent in our culture (usually Oreos are used with rat studies) . At Kartini Clinic we pass no judgment on most of these hyper palatable foods as “bad”, per se, but rather do not build them into the initial food plan in order to bypass that temporary period when the brain seems “on fire” and vulnerable to bingeing and the oft reported effects of overeating and weight gain. Once the system has reasserted its own homeostasis, the parents and child can eat as fits their culture and wishes.
The parent forum Around the Dinner Table refers frequently to children who are refed using high calorie desserts and who can’t seem to stop gaining and eating once their goals are met. This can be very distressing.
A few good references for the effects of PF (palatable foods) on ingestion can be found at http://www.ncbi.nlm.nih.gov/pubmed/9356889, http://ajcn.nutrition.org/content/65/3/717.full.pdf, [and] http://www.ncbi.nlm.nih.gov/pubmed/12213501 — and the statement in the abstract for this last article saying: “Subsequent experiments revealed that binge eating did not occur if only chow was available (Experiment 3) or if restriction-refeeding (R-R) did not proximally precede stress (Experiment 4)”
I guess you could say, we give only chow…..
In the previous post, Charlene looked in-depth at the Minnesota Semi Starvation Study as it relates to the current issue. In this post, Liz looks at the animal research that Dr. O’Toole cited as evidence in support of the Clinic’s guidelines. In particular, Liz focuses on the last paper Dr. O’Toole cited. – Cheers, Tetyana.
In her post, Dr. O’Toole critiques a recovery clinic for handing a patient Cheetos and a soda as part of the meal plan, specifically, as a “challenge food”. While she makes a very fair point that these foods should be enjoyed in moderation, a point that I don’t think anyone disagrees with, I was struck by her rigid requirement of avoiding any “hyper-palatable” foods during the first year of recovery. To quote Dr. O’Toole: “At Kartini Clinic we do not offer our patients ‘hyper-palatable‘ foods for a year following re-feeding.”
First, what are “hyper-palatable” foods and how are they defined? And second, what is the evidence that avoiding “hyper-palatable” foods, particularly for a year, is helpful?
It turns out, Dr. O’Toole derived this terminology from animal studies of binge food intake.
In these studies, the term “hyper-palatable” refers to foods that are high in sugar and fat, and that animals are prone to over-consuming in certain circumstances. Several researchers have used (relatively) cheap and readily available Oreo cookies in studies of feeding behavior as an alternative to purchasing specially made, high-fat rodent diets from a vendor. The use of Oreo cookies to model binge food intake appears to be as effective as using the specially ordered alternatives, but other substances may also be used (e.g., Crisco).
Regardless, what is important in these studies is that the researchers can reliably induce enhanced intake of these foods and examine brain activity associated with this experimentally-controlled behavior. The goal for the researchers is to understand how specific variables (e.g., degree of calorie deprivation, exposure or lack of exposure to high-calorie foods, stress levels) may interact with our neurochemistry to promote binge eating.
The point of this research is NOT to specifically model human behavior, nor inform best treatment practices.
An example of this type of research is Hagan et al.’s 2002 study titled, “A new animal model of binge eating: Key synergistic role of past caloric restriction and stress”. I point out this article in particular because Dr. O’Toole cited it to support her practice in not allowing “hyper-palatable” foods, like Cheetos, Sun Chips, soda, and, most importantly, Oreo cookies, for at least a year.
Dr. O’Toole’s noted that the animals in this particular study did not binge eat when they were given only chow after a period of food restriction and exposure to a stressful situation. Thus, if recovering individuals are only given the human equivalent of “chow” (e.g., rodent pellets) to eat, they will not binge.
First, let’s examine the goal of this study. Hagan et al. (2002) sought to develop a tool to specifically examine the combined impact of stress, a history of food restriction, and exposure to hyper-palatable foods on binge food intake. Thus, they sought to develop a model where animals would binge eat only when these three factors are available:
The goal of this study, therefore, was to test the hypothesis that dieting and environmental stress interact in a synergistic manner to produce binge eating and that access to [hyper-palatable] food is critical to this response. To test this hypothesis, rats were subjected to brief cycles of caloric restriction followed by ad lib [ad lib = without limit] refeeding prior to being exposed to an acute episode of stress via foot shock.
To get this specific “synergistic” interaction, the researchers had to be very particular about how they controlled the rats’ feeding environment. For example,
- The rats had to undergo several cycles of food restriction and re-feeding in order to develop the heightened consumption of Oreos.
- The rats had to be exposed to stress (in this case, an irritating foot-shock) to show this effect.
- The stressful condition had to occur after a restriction and re-feeding cycle.
- The rats had unlimited and unrestricted access to hyper-palatable food.
Furthermore, the rats that had experienced food restriction only enhanced their intake of Oreos when the cookies were made available four hours following the stressful situation. They didn’t show “binge” consumption of Oreos when the cookies were made available 24-48 hours after the stressful situation.
This highly-controlled model of binge food intake is a far cry from the human condition, and its not intended to be an exact model of disordered eating in humans.
The intention of the researchers was to develop a model where the significant factors driving binge food intake were the combined impact of stress and a history of food restriction. With this model, the researchers can potentially uncover brain activity that is associated with this particular predictor of binge food intake.
If we follow Dr. O’Toole’s logic a bit further and assume that the feeding patterns of the animals in this particular study have direct implications for the treatment of eating disorders, then it would mean that individuals recovering from eating disorders would not develop binge eating when exposed to hyper-palatable foods as long as they didn’t experience a panic attack or encounter a stressful situation a few hours prior to eating.
I’m confident that Dr. O’Toole has the best of intentions and has helped many individuals recover from their eating disorders. In this post, I simply wanted to highlight one component of her treatment plan (avoiding sugary, high-fat artificial foods for a year) that, at least to me, does not seem as empirically supported as she claims.
Of course, in this post, I focused only on one article that Dr. O’Toole cited. Nonetheless, I do want to remind readers to be critical of the “evidence” that can often be used to support clinical practices. Just because a clinician cites a scholarly article in support of his or her practice does not mean that the article necessarily supports the claims that are being made.
Hagan, M.M., Wauford, P.K., Chandler, P.C., Jarrett, L.A., Rybak, R.J., & Blackburn, K. (2002). A new animal model of binge eating: key synergistic role of past caloric restriction and stress. Physiology & Behavior, 77 (1), 45-54 PMID: 12213501