Alternate Day Fasting & Classic Dieting: Same >5% Weight Loss in 57 vs. 67 Days W/ Unwittingly Increased Deficits
|ADF vs. continuous dieting in overweight/obese women: ADF marginally faster, about identically satiatin’ but not per se ‘superior’|
“When Weight Loss is Standardized (to 5%), Overweight / Obese Women are Neither Hungrier Nor More Satiated When Eatin’ in an Alternate Day vs. Chronic Energy Deficit. Implications?” ⬅ that’s the title of a #SuppVersity Facebook and Instagram post I was just about to publish yesterday to then decide: ‘Hey, you’ve spent a lot of time to summarize the results of this study. Spend another 10 min (which became 1h) and you’ve got a short news item and hence a new article many of you may be (rightly) waiting for…’
Now, that I am actually in the process of writing it, I also notice other, more tangible advantages: (1) there’s room for figures and, (2) maybe even more important additional calculations; (3) there’s no limit to the number of characters and words, and (4) you have the guarantee that you can always come back to this article as a reference in your online feuds with friends and foes over the one question that has split the health & fitness community in ways that may remind some of you of the partisanship in US politics.
|Figure 1: My plot of the self-reported (baseline and final week of intervention) and prescribed (final week of intervention) energy as well as the relative difference between baseline and end-of-intervention energy intakes (in %) on top of the bars to give you a better idea of what the study protocol actually involved (data from Table 2 in Beaulieu 2020)|
For this study (Beaulieu 2020), which happens to be called the “DIVA” study (even though Maria Carrey was not one of the overweight subjects ;-), the researchers from the UK and the US recruited 37 women with #overweight / #obesity (BMI 25.0–34.9 kg/m²; age 18–55 y) who were then fed energy-restricted diets either continuously #CER (25% daily energy restriction) or intermittently #IER (alternating ad libitum and 75% energy restriction days). Food intakes were assessed using a validated online self-administered 24-h dietary record tool (myfood24.org) over a 7-d period at the beginning and end of the weight-loss period.
|Figure 2: Schematic of the trial. Anthro, anthropometrics; Bfast, breakfast; BW, body weight; EBQ, eating behavior questionnaires; LFPQ, Leeds Food Preference Questionnaire; RMR, resting metabolic rate; SWA, SenseWear Armband; VAS, visual analogue scales for appetite ratings; WL, weight loss (Beaulieu 2020).|
All participants were given specifics meal plans, the energy content of which had been calculated based on measured RMR × PAL obtained from the SenseWear Armband and in line with the subjects’ individual dietary preferences. Adherence to the meal plans was considered when reported energy intake in the weekly meal plan booklets did not exceed the prescribed energy intake by >75 kcal. The average relative macronutrient composition (expressed as % of total energy intake) was identical in both groups when the actual real-world intakes were considered.
|Is intermittent dieting the better form of dieting? Results are promising, but far from conclusive – even in 2018. Check my recent review article in the SuppVersity Archive’s ADF-related articles.|
IER, IDR, IDF or ADF – wtf #acronyms? I personally would say that the study at hand used an #ADF protocol, i.e. a rather significant reduction in dietary energy intake that has to be adhered to alternatingly: You diet on Mo, Wed, Fri, Sun and eat ad-libitum on the other days (days will change from week to week to maintain the scheme) – hence, “alternate day” fasting.
#ADF is also not new and, obviously, you can find a lot of information about it in the SuppVersity Archive at suppversity.com/search/label/ADF.
In reality, though, the overweight/obese subjects cut their calories slightly more than what was required: Their energy intakes went down by…
- -28% for a total deficit per week of -3857 kcal/wk in those who reduced their intakes by cutting 551kcal/d every day (CIE), by
- -67% on the fasting days and quite surprising -10% on the ad-libitum days of the IER group, on which the subjects were allowed to eat “ad-libitum”, i.e. ‘as much as they want’ 😮
This ‘extra-cut’ on ad-libitum days (and hence ‘feasting’ days) implies that the ADF group averaged a deficit of -39% and -9632 kcal/week!
|From the archives: Study Suggests Superiority of Dieting With 2 Refeeds/Week vs. Continuous Dieting learn more! In essence a slightly similar approach to intermittent energy restriction, albeit one that’s harder to handle than the every-other-day ‘refeeds’ on #ADF protocols. Another similar alternative: “Calorie Shifting (Refeeding) for Max. Fat Loss” in overweight women | read more!|
This impressive, automatic/voluntary extra-restraint may, at least partly, explain why the IER group needed 10 days less to lose their weight… with huge standard deviations of 16 days in the IER and still 13 days in the CIE group, though and virtually identical weight loss at the 12-week mark: -6.3 ± 0.8% in 57 ± 16 d, in the #IER group (n = 12), and – 6.6 ± 1.1% in 67 ± 13 d; in the #CER group.
What’s left to report in terms of results?
The satiety quotient which represents the “difference between the subjective ratings of motivation to eat before and after a meal by the ingested energy intake during the eating episode” (learn more) remained unchanged and was similar in both groups. This observation is in line with the identical improvements in dietary restraint, craving control, as well as the susceptibility to hunger, and binge Eating (P < 0.001).
So, everything was the same in both groups? Not exactly: The self-selected meal size decreased after the ≥5 % reduction in CER (P = 0.03) but not in IER (P = 0.19). In other words, the subjects’ perception of what’s a normal meal size improved significantly only when they weren’t allowed to serve as much as they wanted every other day – just like almost all other changes, there was yet no significant inter-group for this ‘learning effect’, either.
The best diet will always be the one you can best adhere to… but if that’s an alternate day fasting, or IER regimen, as it is labeled in the study at hand, this may have significant advantages for some.
The latter are not a result of fasting’s often proposed (and non-validated) metabolic advantage (aka magic, REE remained the same in both groups), though, but rather due to the increased overall energy deficit: from the targeted 25% and the already augmented 28% in the CER group to a whopping -39% in the IER/ADF group that took place unwittingly/automatically and may even have been larger in the ‘biggest losers’, i.e. those who did very well with the IER/ADF diet.
Those who didn’t do well with this form of dieting, though, were according to the FT of the study, not just more likely to overeat on the feed days, they also tended to introduce cheat days and ended up in the group of those who failed to lose the ≥5% within the 12-week period or dropped out (N=6 vs. N=3 in IER vs. CER).
So, if you know you’re going to fall off the wagon on days with a deficit of ~75% or overboard on the ad-libitum dieting / (re-)feed days: Don’t try the IER/ADF approach. If, on the other hand, you’re like many of the subjects at hand and are so happy that you can eat ‘as much as you want’ every other day and thus able to ‘keep your shit together’ or even stay in a marginal deficit (here 10%) on the feeding days, go for it… ah, intermittent energy restriction (#IER) in form of alternate day fasting (#ADF) it’s likely you see benefits, even if those are small | Discuss the study on Facebook!
- Beaulieu, Kristine, et al. “Matched Weight Loss Through Intermittent or Continuous Energy Restriction Does Not Lead To Compensatory Increases in Appetite and Eating Behavior in a Randomized Controlled Trial in Women with Overweight and Obesity.” The Journal of Nutrition 150.3 (2020): 623-633.