A vibrating fork called the “HAPIfork” got a lot of buzz (sorry) last week with promises to help you lose weight, enhance digestion, and improve overall feeling by letting you know when you are eating too fast and thus slowing you down.
I was surprised at these claims, given that I have read some of the research on eating speed and weight and found it mixed, and overall unconvincing. My post on that is here. The research spans back to the 1960s, but curiously, the company only cites research since 2002:
- Ok, let’s review these 3. The 2004 “demonstration” by the North American Association for the Study of Obesity was apparently a conference presentation, and doesn’t seem to have been published after. At least, that is what I can garner from the lead author’s CV. So that doesn’t help us much.
- The “2006” study was published in 2008, and it was only on women, and it wasn’t the University of Pennsylvania (University of Rhode Island)!. A press release came out in 2006 when it was presented at a conference. Interestingly, this is reported incorrectly in lay articles on the web (example that also includes the 2004 reference from above), so it makes me think the company didn’t read the actual research. Perhaps the company misread the comment from Barbara Rolls in this news report on the study who is from Pennsylvania State and wrote University of Pennsylvania? Also note that the meals were ad libitum.
- The “2011” cross sectional study was actually published in 2008. It is what it is, but prospective observational and interventional trials are needed to support causality. The big risk here is that everything is self-reported- eating speed might be pretty subjective. Maybe the company got the 2011 date by getting the information from this Daily Mail article which was published in 2011.
So, not a good start for usefulness/accuracy. They link the slowcontrol.com website so I went there to see what else they cite. Note that there are references there for eating speed and glycemia and metabolic risk, though I only critique their selections for energy intake and weight below. The selected references for the former are as weak and unconvincing as those chosen to support the weight claims.
I first clicked under research posted for “Eating Slowly & Energy Intake”, where they only list 2 references:
- The first reference links to a study (PDF) that uses a fixed-portion meal instead of ad libitum and found that eating speed does not influence satiety or calorie intake- it directly refutes the product’s claims!. This suggests the product would be ineffective in these circumstances (like dieting perhaps)! At least they cite conflicting research, but given that this is the only conflicting study they cite and they don’t comment on it, it seems more like an accident.
- The second study they cite used a vibrating pager to reduce eating speed in 3 autistic participants who have a history of very rapid food consumption. Perhaps this product could be beneficial in this subset of people, for as the study says, “[t]his behavior can lead to serious health problems, such as vomiting and aspiration, and may be socially stigmatizing”. But the company is marketing this to the general population so this is not relevant to the vast majority.
Next, I clicked on “Eating Slowly & Overweight”, which contained 5 references:
- The first reference is a systematic review of eating behaviors and overweight from 2012. Here is a direct quote from the paper:
“Finally, no longitudinal studies were found regarding the inﬂuence on body weight of irregular meals, eating until full (in children) and eating quickly (in adults). Overall, the small evidence on these three eating behaviours does not allow to establish their effect on obesity, even though this relation is biologically plausible (e.g. eating quickly or until full may lead to increased energy intake).
The authors note that behaviors need to be studied simultaneously a framework and existing research is limited in this manner. It is unlikely in my opinion that only targeting one behavior like eating speed will be effective as a general recommendation.
- The second reference is to a position paper (PDF) by the Committee on Nutrition of the European Society for Paediatric Gastroenterology. There is no mention of eating speed in this paper.
- The third reference is to the cross sectional study I discussed above, which is preliminary research.
- The fourth is to a WebMD article discussing that “2004” study used above that was a conference presentation and doesn’t seem to be published. Of note, we learn there were only 6 participants, greatly limiting interpretation.
- The final reference is to the 2008 trial in women that was discussed above. This is the only trial so far that seems to support the product, though note it was only women, a small sample size, and the test conditions were not exactly “real-world”:
“Under the quick condition, subjects used a large spoon (soup spoon) and were told to consume the meal as fast as possible with no pauses between bites. However, they were instructed to not eat so fast that it was uncomfortable for them. During the slow condition they were instructed to take small bites, put down the spoon between each bite and chew each bite 20 to 30 times. A small spoon (teaspoon) was provided with these meals.”
And, this only tell us that “combined techniques of taking small bites, pausing between bites, and chewing thoroughly can decrease the rate of food ingestion, and enhance effects on satiation, decreasing energy intake.”
The discussion of this paper is really good in showing how contradictory the research is:
“Several explanations are possible for these observed relationships between slow eating and reduced food intake, all of which need additional investigation, and none of which are mutually exclusive. First, prolonged meal duration can allow more time for physiological satiety signals to develop before too much energy has been consumed. However, empirical evidence must be provided before this reason can be concluded. Secondly, this protocol used combined strategies to slow eating pace, including small bites, thorough chewing, and pausing between bites. Any of these factors, or synergy between them, might have helped the women to consume less and feel more satiated. For example, the process of chewing itself can stimulate physiological satiety signals  ,  ). In addition, eating slowly allows time for consuming water along with the meal. Indeed, the women drank more water under the slow condition. Although it is possible that this may have increased stomach distension, and thus induced satiety (  ,  ), not all studies have shown that water consumed with a meal reduces energy intake (30). Thus, research is underway in our laboratory to clarify this. Finally, eating slowly allows more time for enjoying food, as supported by the pleasantness ratings in this study. It has been suggested that by slowing down and savoring the sight, smell, taste, flavors, texture, and mouthfeel of food, and sensing hunger being suppressed, more satisfaction can result from fewer calories (  ,  ). However, Kaplan (9) reported that subjects gave higher taste ratings after meals eaten at faster rates as compared with slower rates.”
What they don’t cite
Among some of the conflicting studies against the eating speed/weight hypothesis that I discussed in my post from 2009, one small study from 1997 counter-intuitively found that participants in an ad libitum context actually eat more when made to pause between bites, and rated hunger and fullness as less satisfied compared to no pauses. The authors suggested that the pauses increase frustration and the increased calorie intake is the result of this.
Importantly, even if reducing eating speed reduced calorie intake, there is no data supporting long-term weight loss. Many interventions can acutely reduce calories, but long-term may not lead to any change. There is even one small trial that showed a reduced calorie intake with a slowed rate of eating but they couldn’t maintain this long-term.
In many papers I looked at, authors suggest that it is unlikely that targeting a single behavior like eating speed is a good idea. Instead, other characteristics of food likely confound or influence the relationship with calorie intake. For a good lay article, see this by Barbara Rolls.
It is pretty clear that this company did not carefully review eating speed research and simply cherry picked some studies they think support their product by skimming media reports.
The company’s press release had this headline:
“World’s First Smart Fork That Helps You Lose Weight by Eating at the Right Time and Pace”
I would suggest this instead for accuracy:
“World’s First Smart Fork that won’t help if you are on a diet, might work a bit in circumstances when you can eat as much as you want though there is conflicting data and there may be differences in efficacy by gender and body weight and also we don’t have data on actual long-term weight loss. Additionally, there is no evidence that this fork consistently leads to slower eating nor changes your habits in the long-run”
But I guess that wouldn’t sell very well.
I also want to take the opportunity to plead to tech blogs: new gadgets may seem cool, but please do the work to see if a company’s claims go beyond the data and don’t just regurgitate the press release. This level of egregious misrepresentation of references is on par with many companies in the dietary supplement industry.