Does intermittent fasting works better than conventional dieting for improving fat loss and muscle gaining?
Or it’s all a hype?
Today I’ll compare the 3 most common fasting methods with the conventional methods of dieting and I’ll show you the difference between them and normal dieting.
At the end, I’ll show you what decades of research has to say about intermittent fasting and weight loss.
Is intermittent fasting better than conventional dieting?
I made my first whiteboard video that explains the science behind the intermittent fasting hype and fat loss. Let me know what you think:
- Whole Day Fasting (WDF)
- Alternate Day Fasting (ADF)
- Time Restricted Fasting (TRF)
Let’s start with the first fasting method: Whole Day Fasting
Whole Day Fasting (WDF)
A whole day fasting strategy involves fasting 1-2 days a week for at least 24 hours.
Harvie et al (1) compared the effectiveness of whole day fasting versus a conventional caloric restricted diet for weight loss, insulin sensitivity, and other metabolic disease risk markers on two groups:
- A whole day fasting group that had 2 fasting days of ~647 calories/day for 2 days a week
- And the control group that had a daily caloric intake of ~1500 calories/day
They controlled the weekly energy deficit over a 6 months period and made sure the total deficit was equal between both groups.
He saw no difference in body fat reduction between the whole day fasting group, and the control group over the period of 6 months.
CONCLUSION: Whole day fasting is an effective dieting strategy for weight loss as long as you create a weekly caloric deficit, and you don’t suffer from an eating disorder condition (I’ll tell you why in a minute)
Let’s go to the next one:
Alternate Day Fasting
This is the most studied method of fasting. Alternate day fasting typically involves a 24h fasting window followed by a 24h feeding window.
The main premise behind this type of dieting is to create a big deficit on the fasting day but not compensate with more calories on the feeding day so you can still maintain an overall weekly deficit.
Is alternate day fasting causing more weight loss compared to a conventional diet?
Catenacci et al (2) compared the changes in weight, body composition, lipids, and insulin sensitivity of ADF with those produced by a normal weight loss diet with moderate daily caloric deficit.
They took 26 people, split them in two groups. One group (14 people) was put on a zero-calorie ADF diet and the other group (12 people) on a daily caloric restriction of 400 calories. Both groups did this for 8 weeks.
They found out that at the end of those 8 weeks, there was no statistical significance between both groups in terms of weight loss and body composition.
- The ADF group lost 8.2 +- 0.9 kg
- The normal dieting group lost 7.1 +- 1 kg
There was a follow-up where scientists gathered the people after 24 weeks to check if they regained the weight they lost during the experiment.
They saw no difference in weight regain between the 2 groups.
CONCLUSION: ADF causes similar weight loss as with a normal dieting strategy, and does not appear to cause weight regain.
The last one is the most popular method of fasting: the 16-20h fast with a 4-8h eating window
Seimon et al (3) published one of the largest systematic review of intermittent fasting.
This review was formed from 40 studies in total from which 12 of them looked at the effect of intermittent fasting on weight loss and compared it with a normal caloric restricted diet.
They found out that both of these diets resulted on similar changes in body composition, and weight loss.
They even looked at their effects on thyroid, sex hormones, and cortisol and saw no differences between IF and the conventional caloric restricted diet.
WRAPPING IT UP
Intermittent fasting is nothing special.
There’s no “stroking of the metabolic furnace”, there’s no “increased fat loss”, there’s no special effect that creates fat loss out of thin air.
I’ve been saying this for years. But too many people are being hyped up and lied about this dieting strategy: Intermittent fasting is just a dieting strategy you can use to help you stay consistent on a diet with a caloric deficit.
I am not fasting anymore because I don’t want to impose “feeding and fasting windows” on my time. I simply eat whenever I feel the need and my body asks for. Of course, I control my caloric intake most of the time.
You should look at your lifestyle and ask yourself this question:
Is intermittent fasting improving my adherence through its simplicity, convenience, and flexibility?
If it helps you stay on track easier, then go for it.
If you liked my blog and want to see more like this one, give it a like and share it with a friend. If you know someone that’s really into intermittent fasting, send them this article and video. It might be an eye opener for them.
- Harvie MN1, The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women., Int J Obes (Lond). 2011 May;35(5):714-27. doi: 10.1038/ijo.2010.171. Epub 2010 Oct 5.
- Catenacci VA1,2, Pan Z3, Ostendorf D2,4, Brannon S5, Gozansky WS6, Mattson MP7,8, Martin B9, MacLean PS1,2, Melanson EL1,10, Troy Donahoo W1,6., A randomized pilot study comparing zero-calorie alternate-day fasting to daily caloric restriction in adults with obesity., Obesity (Silver Spring). 2016 Sep;24(9):1874-83. doi: 10.1002/oby.21581.
- Seimon RV, Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials., Mol Cell Endocrinol. 2015 Dec 15;418 Pt 2:153-72. doi: 10.1016/j.mce.2015.09.014. Epub 2015 Sep 16.