Lose Fat With Mini Fasting
Last month we were lucky enough to get Toronto based nutritionist Brad Pilon on the Reality Based Fitness Podcast. Brad talked about the concept of 24-hour intermittent fasting and how it could be used for fat loss.
While Brad favors the 24-hour fast, this may be a little harder to accept for some individuals. A new study just published in Medical Hypotheses, A “mini-fast with exercise” protocol for fat loss (July 2, 2009) looked at the results of using small 12-14 hour fasts with exercise.
The research details
Twenty-seven subjects (10-female and 17-male) participated in the study. During every 24-hour day, the subjects were instructed to have a 12-14 hour fast during which they were also asked to participate in moderate intensity exercise. Subjects were encouraged to perform exercises in which they had to support their own body weight - IE, treadmill, stair climber, elliptical, etc - and to work up to 45min. of continuous activity.
The exercise and fasting protocol could have been performed whenever was convenient for the subject:
- If they wanted to exercise in the morning, they would skip breakfast and not eat until lunch.
- If they wanted to exercise in the afternoon, they would skip lunch and not eat until dinner.
- If they wanted to exercise in the evening, they would eat a light dinner. Wait approximately 2-hours and then exercise. Following exercise, they would not eat until breakfast the next morning.
Subjects were given some food selection guidelines, which instructed them to maintain a diet low in saturated fats and high glycemic carbohydrates; however, caloric intake was not restricted.
The research findings
Following the 12-week protocol subjects had an average weight loss of 4.2kg (9.25lbs). More impressively, the subjects saw an average 7.4kg loss in fat mass (16.28lbs), corresponding to a 25% reduction in initial fat mass! In addition, there was a 25% reduction in fasting insulin (possibly showing enhanced insulin sensitivity) and an average waist circumference reduction of 7.9cm.
Interesting facts about the findings
- Subjects were not supervised during this study! That is a huge problem with most studies conducted on dietary and/or exercise interventions for weight loss, as subjects typically over-estimate caloric intake and/or under-estimate exercise activity. So, without someone standing there watching them every minute of the day, subjects basically self-sabotage themselves. Perhaps the flexibility of the guidelines in this study made it easier for subjects to adhere to.
- A questionnaire revealed that a number of subjects were only intermittently compliant with the program. This is particularly interesting given the results! If the subjects were only moderately following the program plan and they had these kind of results, imagine what would have happened if they were religious about the program. The male subject who followed the program perfectly saw a 20kg (44lb) loss of fat while the most compliant female (40-years old) lost 14.1kg (31lbs) of fat.
- Fat loss in the second half of the study was slightly greater than in the first half of the study. This is interesting to note, because typically studies on fat loss show a decrease or plateau in results after a certain period of time. This suggests that if the study had been carried out for longer than 12-weeks, we may have still seen even greater results.
- The ease of the studies protocol and the fact that subjects did not have to adhere to a specific caloric intake or worry about not eating carbohydrates, showed that subjects who are motivated can achieve significant fat-loss without having to over-complicate their diet - a problem that is common in today’s world of information overload.
- None of the subjects in the study exercised more than 1-hour per day and they all had at least two rest days each week.
- The authors note that while this study used moderate aerobic exercise for in its protocol, brief periods of intense interval training may illicit greater results with regard to fat oxidation.
- The authors concluded that this protocol might be beneficial for individuals seeking weight loss as it is easy to follow and does not require emphasis on calorie or carbohydrate counting. This is particularly important for individuals in the “real world” who lead busy lives. The authors did take a jab at a favorite American reality show without actually naming the name (BIGGEST LOSER) by stating:
“A currently popular American TV series is regaling viewers with exploits of overweight volunteers who lose massive amounts of weight by engaging in several hours of vigorous exercise daily while consuming semi starvation diets. Yet for most people such a regimen would be both impractical and unsustainable. It would actually be a lot more impressive and meaningful to watch people cutting their body fat in half while holding down a full-time job, raising a family, and enjoying their meals.”
Conclusion
Judging by the results the subjects in this particular study had, I think it is safe to say they were relatively over-weight/de-conditioned individuals who may (or may not) have had much exercise experience. However, this should not discourage you if you are an avid exerciser who is not satisfied with your results. If anything, the brief periods of fasting and the fact that you can handle greater intensities of training (remember what the researchers noted above) leaves the door wide open for you to still have some impressive results. Especially given the fact that you don’t have to sit there and be miserable counting carbohydrates all day and failing on the plan or falling off the wagon like so many do each year.
Just to give you an example of how I set it up, I have been doing one 24-hour fast each week and then a few short mini-fasts on other days. I don’t have the goal of weight loss or fat loss, mainly just maintenance, so I don’t do the fasting every day. I lift 3-days per week (Mon, Wed, Fri) performing total body workouts on each day. Each of my lifting days I perform intervals at the end of my resistance training. On in between days I perform moderate cardio or tempo runs and it is on these days that I place my fasting.
Give fasting a shot. Whether you perform a 24-hour fast or the short mini-fasts I think you will be delighted with your results.
Good luck!
Patrick
patrick@optimumsportsperformance.com
13 comments
Does this type of fasting include water fasting?
Emilio,
I don’t know what you mean by water fasting. If you are asking me if you should drink water during the fast, the answer is YES.
Patrick
this is the routine I used to lose 25 lbs in 5-6 weeks. BUT I also watched my calorie count. I could easily eat 6000 calories a day and would not be losing weight that way. By fasting before exercise and eliminating the carbohydrates, proteins, and fats ingested before a workout, your body is going to use the ATP-CP and glycogen stores for energy, once those are used up (probably minutes) your body will also be using fat stores as a main energy source. The problem with this study is that if you do not replace your glycogen stores IMMEDIATELY after a workout, you will have less glycogen stored for next time. While this is beneficial for weight loss, it is also detrimental to increasing energy levels be able to last as long during exercise
While it’s interesting and need to read this more, you didn’t mention a control arm. That would seem to be a requirement for any study.
There have been many more studies on the concept of intermittent fasting. This was just the newest one. Others have control groups.
I do think a control group would be silly in the case of this study. “We had a group who just went about their daily lives, eating crap and not exercising….They gained weight in the 12-week period.”
patrick
I do think a control group would be silly in the case of this study. “We had a group who just went about their daily lives, eating crap and not exercising….They gained weight in the 12-week period
LOL - funny and true. Anyway, this sounds like the warrior diet a bit doesn’t it? (of course with a bit more flexibility in that you can pick WHEN you are fasting vs. always fasting up to dinner) I think this is great for short-term fat loss or “cutting” but not something any strength athlete or BB’er would do longer than say 8 weeks or so. I would worry about muscle catabolization. It would be interesting to see more data on this study regarding fat vs lean muscle loss/gain? I would think the once a week 24 hour fast has to be less detrimental to lean muscle than 5-6 days of mini-fasts, seems a bit much to me… Anyway, very interesting stuff here and worth doing more research/trials on.
Troy,
Your concerns are the concerns that many have; however they are not completely correct. Actually, the metabolic rate in humans goes up after 3-days of fasting (I believe that was in one study. Would have to check with Steven Bubel on that one to be certain).
In addition, muscle catabolism does not just happen. You would have to do something significant for an extended period of time. If you are lifting, that is the prime “driver” which is providing adaptation for muscle maintenance.
There are many studies out there talking about your concerns. Pick up Brad Pilon’s book, Eat-stop-eat, as he covers this pretty in-depth. I have been fasting since May with no ill effects on strength (I actually am getting stronger) or muscle loss (I am leaner now that I have been in a while and I am maintaining my body weight).
It isn’t about what you “worry” about, it is about what takes place in our bodies - which are highly adaptive mechanisms. Most people fall prey to BB’ing voodo and nonsense that is published in magazines and on the internet (IE, the whole 5-6meal a day crap). When you actually go and check some of this stuff out, it doesn’t pan out.
Patrick
Patrick
I’m wondering why you are doing these fasts if you are in maintenance mode? Surely this is not necessary with the exercise you are doing?
I agree about the 5-6 meal a day thing being crap. Abandoning this slavish approach has freed me up and actually been a huge weight off my shoulders.
Regards
Colin,
I use the mini-fasts to maintain my weight/BF% because it is much easier than trying to live this entirely strict lifestyle and be as lean as I want to be. It is much harder to count calories all day, watch every single thing that goes into my mouth and worry about all that stuff than just not eat for a mini-fast and then eat normally after that.
patrick
45 minutes of cardio/7 days a week. And the fasting is concluded to be the determining factor for this group’s weight loss? Why would a control group doing the exercise component without fasting be silly?
I guess it wouldn’t be “silly”. But, I just don’t see the control group making much progress without a controlled diet (although they were over-weight deconditioned people, so any exercise they do will illicit some sort of result). This particular study was “medical hypothesis”, which is probably why there was no control group.
patrick
Thanks for the response.
In my “formulation” on how this study would be useful, the control group would have restricted calories as well — they would just be required to eat such that the time between their meals wouldn’t put them in the fasted category. Then compare weight loss in terms of rate and maybe adherence to the protocol.
Otherwise, I was like yeah exercise and restrict calories should equal lose weight with or without fasting.
Cheers.
Hey Tacey,
I think your formulation sounds good. You are correct, restrict calories and move is pretty much a “no-brainer”. The thing with caloric restriction is that most people have a difficult time always counting calories and analyzing everything they put in their mouth. In addition, research shows that people more often then not under-estimate their caloric intake and over-estimate their exercise activity. The reason that some have seen great results with fasting is because they just don’t eat. There is nothing to count, there is nothing to add up. You just don’t eat and then after the fast you go right back to eating your normal diet. So, instead of counting calories every day and being “miserable” as so many are on a diet. They just do a short fast and get create their caloric deficit that way. In this study, the subjects fasted daily. In Brad Pilon’s book he says to do a 24-hour fast every 4 or 5 days. Either way, you create a caloric deficit and you don’t have to count calories and carbs and get wrapped up in the mind game of diet (if that makes sense?).
Thanks for checking out the blog.
Patrick
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