Intermittent Fasting – Does it Work?

There are all kinds of diet trends out there – Low carb, the Keto diet, the Mediterranean diet – but the latest trend?

Intermittent Fasting

Now, this has been around for awhile, but like everything, it’s experienced a resurgence and there are some studies showing that it can actually help you lose weight.

I want to talk about a study that was published in the Journal of Nutrition and Healthy Aging. In this study, they had 23 obese women change their diets so that they were only eating between 10 a.m. and 6 p.m.

In that time, they could eat anything they wanted – although they could only drink water or calorie-free drinks.

After 12 weeks, the group had lost about 3 percent body fat and were eating about 350 fewer calories, which is surprising. They weren’t restricting anything, yet because they didn’t eat after 6 p.m., they naturally ate less.

Keep in mind, this is a tiny study, but interesting. And it kind of leads into another tidbit I found related to restricting your eating to certain hours.


They found that the time of day had a big impact on hunger levels and that we have a stronger perceived appetite at night. They found that stress can increase hunger hormones in the evening, which is one reason some of us end up bingeing at night.

The takeaway here is this: Creating a window of time for when you eat may help you naturally reduce the calories you eat. So, perhaps cutting off your eating at 6 p.m. or 7 p.m. would be one way to test this theory out.

One more thing – If you’re interested in intermittent fasting, there a number of ways to do this. You can fast on alternate days, fast for certain hours, skip meals…it gets confusing. But this article, Intermittent Fasting: A Primer offers some great information about the different ways this can work.

So, what do you think? Have you tried it? Would you try it? Leave a comment and tell us about it!


  1. Tom Owen says:

    I am 70, 6 ft, and on the way down from 193. I have – with my cardio’s permission – used IF for 2 weeks. Mostly 16 or 17 hour fasts 4 days a week with a solid lunch and dinner. One 24 hour fast. Have kept exercising – 2 lifting sessions at the gym with a trainer, and two or three 45 minute aerobic (usually Peloton) sessions (though not on the 24 hour fast day!) Three “normal” meals other days, but a bit healthier than before I started IF. Blood pressure is already down and have lost over 6 pounds in 2 weeks – bear in mind this is without “conscious” calorie restrictions, though (again) I find myself eating healthier foods and enjoying those foods a LOT more. Much of it probably comes from not eating after 6:30 ish – I am normally in bed by 9:15 but could routinely have a cup and a half of yogurt ice cream (yogurt is good, right?) and a few oatmeal raisin cookies (same argument). I am a bit concerned about the “lowering my metabolism” argument though frankly some research, including NIH stuff, is saying this risk is overstated.

  2. Rich says:

    This is great information! Like all thought provoking articles, it leads to a couple of questions:
    1. It’s been said that working out fasted can burn fat more effectively, since glycogen stores are depleted; given that, what is the fasting window required before a cardio workout (power walking 15 min/mile or running 11-12 min/mile)?
    2. Similar to above, but for 21 minute HIIT dumbell workout?
    And finally, Paige,
    3. What about 1-1.5 hour gym sessions (Barbell work: Squats, Deadlift, Bench Press, plus pullups, dips, leg raises).
    As always, thank you Paige for sharing your expertise!

    • Paige Waehner says:

      Hi, Rich – Those are really excellent questions. The answers really depend on what kind of intermittent fasting you’re doing, so here’s the breakdown:
      If you’re doing 16 hour fast/8-hour eating window, you can typically do cardio or strength training in a fasted state – and yes, some studies show that you do burn more fat in a fasted state (not all). What you really want to think about is this: If you’re doing intermittent fasting AND exercise, you want to try to time your workouts during your eating window because remember, it’s really important what you eat AFTER your workouts (especially high intensity and strength training) to repair and regenerate. Especially true if you’re doing an hour of weight training in the gym – you want to have some protein and carb mix after that. And of course, it depends on whether you exercise well on an empty stomach – may be different for everyone. What many experts suggest is that over time you can get used to working out in a fasted state. BUT if you’re more of an athlete, working out for more than an hour every day, IF may not be a great option because you need to fuel those workouts. Does that help? LMK – This is definitely an ongoing discussion in the fitness industry.

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