Is There Any Benefit to Intermittent Fasting?

What if I told you that you could you drop over 15% body fat in 8 weeks without losing any muscle by just switching the time of day you eat?  Does it sound too good to be true? That’s exactly what researchers from University of Padova in Italy wanted to find out. In fact, they discovered that the average fat loss was 16.4 percent.

How can someone lose so much fat so quickly? Intermittent fasting.

What is intermittent fasting? explains:

Intermittent fasting is an eating pattern where you cycle between periods of eating and fasting.  It does not say anything about which foods to eat, but rather when you should eat them.


There are several different intermittent fasting methods, all of which split the day or week into eating periods and fasting periods. Most people already "fast" every day, while they sleep. Intermittent fasting can be as simple as extending that fast a little longer.

The study

Researchers took thirty-four 29 (+/-1 year) year old males who performed resistance training 3-5 times per week for at least 3 years. They randomly divided the men into 2 groups:  Intermittent Fasting (IF) or Standard Diet (SD). The IF group incorporated what is known as the 16/8 intermittent fast. 16 hours of no food of any sort followed by incorporating their 3 meals inside of 8 hours.  

Both groups ate the same number of calories as they did prior to the study, but the timing of the meals changed for the IF group. The IF group ate their meals at the following times:  1pm, 4pm, and 8pm. The SD ate meals at 8am, 1pm, and 8pm. After dinner, neither group ate until their allotted time for breakfast. Both groups had 1 hour to complete each meal.

The nutrition breakdown was as follows (caloric intake was kept the same during the same during the 8 weeks study as the subject had reported previous to the study. All thirty four subjects ate within +/- of 1-2% of below breakdown).  

2,800 calories per day

53% carbs

24% fat

21% protein

(Percentages were +/- 1-3% of target numbers)

No snacks were allowed for either group except 20 grams of whey protein 30 minutes prior to exercise.

The resistance training program consisted of 3 workouts consisting of 3 sets of 6-8 reps to momentary muscle failure with 3 minutes of recovery between each set and station:

  1. Bench press, incline press, dB fly, bicep curls

  2. Military press, leg press, leg extensions, leg curls

  3. Wide pull down, rev grip pull down, tricep press down

After 8 weeks, the researchers found something interesting.  The intermittent fasting group lost an average of 16.4% body fat vs the control group, who lost 2.8% body fat.  The IF group had not lost a pound of muscle. In fact, both groups gained a few pounds of muscle and strength.

*Note:  One key piece of information that often gets overlooked is the fact both groups ate the same amount of calories (2,800).  In order to make sure you are consuming enough calories, you should have your Resting Metabolic Rate (RMR) checked.

Is there a bad time to intermittent fast?

While the study above showed great progress in body fat reduction, like everything else; there is a time and a place. WebMD explains:

Certain groups of people shouldn't fast, though, including women who are pregnant or breastfeeding. Fasting is also not recommended for some people with diabetes, because it can lower your blood sugar to dangerous levels. And avoid fasting if you're recovering from an illness or being treated for cancer and you need to maintain or gain weight.


This style of eating isn't a good fit for everyone. Varady doesn't recommend it for people with binge eating disorder, who could overeat during their "on" days. And if you're a snacker who can't go more than a few hours without food, other eating plans might be better for you.

In my professional opinion, I would incorporate some sort of fasting for up to 8 weeks once or twice a year but then go back to normal eating habits between each fast.  It will help “jump start” your body fat reduction with minimal negative side effects.

What should you do?

Incorporate intermittent fasting for up to 8 weeks once or twice a year. Make sure you’re consuming your normal calories in your 8 hour window. It may be harder than you think to consume those calories in such a short period of time. Make sure that you still keep challenging yourself during your lift. The subjects each hit momentary muscle failure during each lift 3 times per week. In order to have energy for your lifts, incorporate 20 grams of protein powder 30 minutes prior to your lift but this will be your only snack of the day.If you are planning to get shredded for the summer, this is a great way to get yourself back on track of your New Year’s goal.

Steven Zahn 

ACE Certified Personal Trainer

NASM Certified Personal Trainer

Pre and Post Partum Certified

Dragondoor Publications: HKC Russian Kettlebell Certified

For information on 1on1 Personal Training or Nutrition Coaching, feel feel free to contact me at