Intermittent fasting 101: What is it and will it help me lose weight?

6th August 2018

In a nutshell, intermittent fasting is just that: fasting intermittently.


The definition of fasting is quite simple. I’ve read through countless dictionary entries and website descriptions of fasting, and have decided that the best definition of fasting is the following: “The act of willingly abstaining from some or all food, and in some cases drink, for a pre-determined period of time.” The key word in this definition is “willingly” as it is the difference between fasting and starving. Other than this one small difference, the net result is the same – the purposeful abstinence from caloric intake over a given period of time.


Some would say that it’s a more natural way to eat because humans evolved without refrigerators, drive-throughs, or 24-hour shops. We now have access to food (including junk food) all day long, so eating several meals per day plus snacks may be less natural than fasting from time to time.

In other words, a diet’s success can be measured by how well they can enforce my first nutrition ‘truth’ – ‘prolonged caloric restriction is the only proven nutritional method of weight loss’. If the diet plan allows you to stay on the diet for a long period of time, then you have a very good chance of achieving sustained weight loss success. From what we have seen, there is a large amount of science that supports the use of short term fasting as an excellent way to create a dietary restriction, and it seems to be an effective and simple way to lose body fat (which is ideally the goal of ANY weight loss program). On top of that we have also determined that short term fasting does not have a negative effect on your metabolism. So far, so good. Fasting does not cause any negative or damaging effects on our metabolisms,


There are lots of variations on this theme. They include:

– 16/8 which is 16 hours of fasting, and eating only within the other 8 hours (often 12:00 pm. – 9:00 p.m.);

– 5:2 days of fasting, where you eat regularly for five days of the week, then take in just 500-600 calories/day for the other two (non-consecutive)

– 24 Hour complete fast


Is intermittent fasting effective for weight loss?


Intermittent fasting can help to lose weight because it can help you to eat fewer calories, and burn more calories too.


Lots of people say they have success with it. But what do the studies say?


According to one review study, intermittent fasting helped people to lose 3-8% of their weight over 3-24 weeks.  In this study, people also lost 4-7% of their waist circumference (i.e., belly fat).


Another study of 100 people with obesity showed that after a year, the people who fasted on alternate days lost more weight than people who didn’t change their eating pattern. But, (and here’s where it’s interesting) they didn’t lose any more weight than those on a calorie restricted diet. Out of the people who were to follow the intermittent fasting protocol, 38% of them dropped out.


Sticking with a diet is one of the keys to weight loss success. So, if you can’t stay with a weight-loss diet, you’re less likely to lose the weight and keep it off.

It was this revelation that led me to review all the research I could find on the metabolic effects of short-term fasting. By the time I was finished, I had found that in  a very impressive volume of published peer reviewed scientific studies, short-term intermittent fasting has been shown to have the following health benefits:

• Decreased body fat & body weight

• Maintenance of skeletal muscle mass

• Decreased blood glucose levels

• Decreased insulin levels & increased insulin sensitivity

• Increased lipolysis & fat oxidation

• Increased Uncoupling Protein 3 mRNA

• Increased norepinephrine & epinephrine levels

• Increased glucagon levels

• Increased growth hormone levels

• Decreased food related stress

• Decreased chronic systemic Inflammation

• Increased cellular cleansing

Quite a list, I’m sure you will agree. What is even more amazing is that many of the benefits were found after as little as 24 hours of fasting!


Before you consider intermittent fasting


Intermittent fasting is not for everyone. People who are underweight, or have eating disorders shouldn’t fast. Neither should women who are pregnant, trying to get pregnant, or are breastfeeding.


Certain medical conditions can be worsened with longer periods of fasting. Also, people taking certain medications can be prone to side effects with intermittent fasting as well.


One of the reasons people drop out of the intermittent fasting eating pattern is that it’s hard to stick with the fasting part. They eat more than the allowed (low-level of) calories when they’re supposed to be fasting. And when they finish fasting, they may overindulge due to the reaction of the appetite hormones and hunger drive while fasting. None of these will help with weight loss.


Also, the hours and days of fasting can be very difficult. So having strong social support will be key to those intermittent periods of fasting. Sticking to a (healthy, nutrient-dense) weight loss diet is the key to success, and intermittent fasting can be difficult for many people to stick with.




Intermittent fasting is a weight loss trend that seems to work for some people. It can help to lose weight and reduce belly fat. But, it isn’t safe for everyone. Many people should not try intermittent fasting because it can be risky. It can also be difficult to stick with.


For the best chance of long-term weight loss success, finding a diet, you can stick with is key.


What about you – Have you or someone you know tried intermittent fasting? What were the results? Let me know in the comments below.


Recipe (Whole food): Almond Butter Energy Bites


Makes about 12 energy bites


1 cup oats

⅔ cup almond butter

½ cup chocolate chips (semi-sweet and dairy-free if possible)

½ cup flax seeds, ground

2 tbsp honey



Combine all ingredients in a medium bowl and stir.


Using a tablespoon to measure, roll into about 12 energy bites.


Serve & enjoy!


Tip: You can roll the bites to coat them in cocoa powder for a bit of extra flavour and to prevent them from being too sticky.