Practical Tips on how to use Intermittent Fasting for Fat Loss (Many Studies included!)
I’m sure you’ve heard of Intermittent Fasting (IF) before. It is basically specifying when you should eat instead of what you should eat. Many claim that IF can not only help with fat loss, it can improve cardiovascular health, decrease cancer risk and even increase lifespan! But it seems counter-intuitive, doesn’t it? After all, IF is skipping meals for hours or even days, and then feasting within a designated time frame, which seems to be going against the norm.
But fasting isn’t a new concept by any means. Our ancestors have actually been doing it during our hunter-gatherer days, where they have to fast for days if they are unable to find food. IF is just a rebranding of this. Furthermore, we are actually already fasting when we are asleep. And some of us are already doing IF but may not even know it! Most commonly known as skipping breakfast.
So what is the truth? Can IF magically help with fat loss and other benefits? And if so, how exactly should you do IF to see the best results? Here I’ll be covering the types of IF, benefits and shortcomings of IF, how long to fast for, and how much to eat. Let’s dive in.
Fasting is nothing new. It has been around since our hunter-gatherer days.
Types of Intermittent Fasting
The 16:8 Diet
This method involves fasting everyday for 16 hours and then eating within an 8 hour window. Within this window you can eat as many meals as you want. This is the most popular method of IF because it is as simple as skipping breakfast and not eating anything after dinner.
The 5:2 Diet
This method involves eating 5 days a week while restricting yourself to 500-600 kcals for 2 days of the week. For example, you eat normally for everyday of the week except Tuesday and Friday. During these 2 days, you eat 250-300 kcals per day.
Eat Stop Eat Diet
This involves a 24 hour fast once or twice a week. You can either fast from breakfast to breakfast, lunch to lunch, or dinner to dinner. It can be quite difficult for many.
Alternate-Day Fasting
This involves fasting every other day. For beginners, it is not recommended to go on a full fast every other day. Instead, to allow about 500 calories during fasting days. For many, hunger can be a problem and therefore not sustainable in the long run.
The most common type of IF is the 16:8 diet, due to its simplicity.
As you can see, there are many different ways to do IF, which can make it confusing. More importantly, this makes it difficult to test the effectiveness of every single one of these diets. Therefore, you should find one that works the best for you.
Benefits of IF
Fat Loss
And here comes the most important question - does IF help with fat loss? Let’s answer this question with the largest systematic review covering 40 studies investigating the physiological benefits for IF. The study found that IF does not provide any direct benefit for fat loss compared to normal dieting when calories are equated. This means that at the end of the day, what produces fat loss during fasting is still being in a calorie deficit. There is nothing magical about the act of fasting.
But does that mean that IF will not help with fat loss? There are 2 studies that show how IF can help with weight loss in overweight adults. It was not because IF directly helped them with weight loss, but because caloric restriction allowed these individuals to stick to their caloric deficit better. Also, when you’re skipping meals, it is more likely that you’re in a caloric deficit. Last, IF means larger and more satisfying meals which can help you stay full longer.
Therefore, although IF does not directly lead to fat loss, I do recommend that you try it as it may help you with adherence which is the most important factor for dieting.
The most common misconception about IF is that it magically helps with fat loss.
Hunger Levels
Because of long periods of time without food, some people expressed skepticism over hunger for IF. However, there are studies that show how IF can help with hunger levels. In the same systematic review above, it appears that IF may reduce appetite. This is in line with other studies where participants who did IF found a decrease in weight without an increase in hunger levels. This is because while there may be an adjustment period where you can feel hungry at the few days or weeks of IF, maintaining a regular eating pattern will help with hunger levels through suppressing your hunger hormone (Ghrelin), just like any other diet. This is seen in this study.
Suppressing hunger is especially important when you are in a caloric deficit because most people fail their diets due to high hunger levels.
Other Health Benefits
The other health benefits include improved cardiovascular health, neuroprotective effects, decreased cancer risk and lower inflammation, to name a few. It is not fully understood why IF leads to these health benefits, but a theory suggests that food deprivation serves as an acute, mild stress that is good for the body, as your body prepares itself for future stresses in the future. These health benefits are seen in studies done in mice.
Shortcomings of IF
Sustainability
Some may not be able to fight off cravings on fasting days well. This can backfire your diet plans by binge eating during your eating window.
Also, to completely not eat on certain days can limit your social life. For instance, what if you have a birthday party on your fasting day? Are you able to resist peer pressure and not eat at all?
Other Health Benefits
While the studies were done in mice, those done in humans showed no effect on certain health markers. Furthermore, these studies are not done in the long term. Most of the studies were done in the short-term. Although you may see a benefit in the short-term, we will not know for sure if that benefit still holds up 5 years down the road.
There are also potential side effects that some people experience, including headaches, irritability and heart burn.
Declining food at a birthday lunch to stick to the fasting window can be extremely difficult for many.
With the above being said, I still do recommend trying IF for at least 4 weeks to see if it works for you.
But what are some practical tips on how you should fast? Let’s read on to find out more.
How Long to Fast for
With the many fasting methods available, it can be difficult to choose what’s best for you. For the general population, I would recommend the 16:8 diet as it is simply skipping breakfast and not eating anything after dinner. For example, only eating from 12pm to 8pm, and fasting for the rest of the day. If you struggle with fasting for 16 hours, 7 days a week, you can always start with fasting for 14 hours, 5 days a week, before slowly progressing to longer hours and more days of the week.
On what time to fast, you should find what’s best suited to your lifestyle, as the timing of fast does not matter. Most importantly, the time of fast has to be consistent throughout the week. For example, you shouldn’t be fasting from 12pm to 8pm from Monday to Friday, then fasting from 2pm to 10pm on Saturday and Sunday. As mentioned above, this will not allow your body to adapt by suppressing your hunger hormone, Ghrelin, during the time of your fast. This is seen in this study. However, do note that your body will take about 2-3 weeks to adapt to it.
A regular eating pattern will help to curb hunger pangs.
What and How Much to Eat
On what to eat during your fasting window, it is as simple as not eating or drinking anything that has calories. That includes everything except water or drinks with zero calories., like tea or black coffee. Drinks with artificial sweeteners instead of sugar work too.
On what to eat during your feeding window, it is simply eating what you usually eat if you’re not fasting. That is eating mostly whole foods and adding some ‘fun’ foods after.
On how much to eat, it will largely depend on your goals. If you’re trying to lose weight, you should skip breakfast and eat your usual lunch and dinner during your feeding window. It is important that you do not eat a heavier lunch and/or dinner than usual just because you are in your feeding window. Remember that at the end of the day, it is the amount of calories that helps in weight loss, not the act of fasting. However, if you’re trying to gain weight, IF may not be ideal for you. This is because studies have shown that eating lesser and larger meals compared to smaller and more frequent meals will get you full longer.
You shouldn’t be eating or drinking anything during your fasting window, other than calorie-free drinks like plain tea or coffee.
Conclusion
IF can be a good way to lose weight if you are able to be consistent with it. If the hunger cravings are too strong for you and you end up overeating during your eating window, then it defeats the whole purpose on IF to being with.
The best diet is still the one that you can adhere to the best.
P.S. - need personalized tips for fat loss? Drop me a message!
