Intermittent Fasting: Busting Myths & Hidden Truths!
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Busting Myths and Hidden Truths!
Would you like to lose fat while eating whatever you want and not having to cut out junk foods from your diet?!
The correct answer is “yes”. It’s this exact problem that has sold Intermittent Fasting (IF) to so many people – the promise of an easy approach to dieting that will improve everything from body fat to diabetes.
We’re going to take you through everything you need to know about intermittent fasting – from the effects on your health, aesthetics to the myths about IF.
We’re not here to do a hatchet job – there are benefits to Intermittent fasting – but you need to know what’s true and what’s marketing hype!
What is Intermittent Fasting?
If you’ve been paying attention to the diet and fitness market for the last few years, you’ll know that Intermittent Fasting is a popular approach to diet based on periods of fasting and feasting/feeding.
There are a few ways to pull this off, but the most popular (“normal”) approach to intermittent fasting is to fast for around 16-20 hours a day and eat between a 4-8 hour window. This might mean not eating except for between the hours of 4pm and 10pm.
The point of this is to reduce the amount of food you consume – in this way, you can use IF to manage your calorie intake. It takes a lot of willpower to fast for up to 20 hours, but it has some benefits. We’re going to discuss the benefits and drawbacks later, but the point of intermittent fasting is to cut calories and manage hormones/satiety.
If you’re eating 2500 calories in 4 hours, you’re probably going to get full pretty fast which means over-eating is actually just difficult during these hours!
Fasting and Feasting Windows
The way that fasting and feasting are balanced is mostly up to you and your needs. Your schedule and the number of calories you use is a big factor in how long you can go without food. There are some real problems with super-long-term fasting, so it’s often advised to start with shorter fasts: 20-hour fasts are tough to pull off for a beginner!
Feeding windows are all about getting all the high-quality nutrients possible and making sure that you’re refueling for exercise, life and the next fasting block. They tend to be later in the day to allow for the best results and avoid any hunger-related problems.
If you have digestive problems, however, make sure that your feeding window ends at least an hour before your normal sleeping times. Eating a lot of food before bed is linked to problems with digestion if you suffer from IBS or any similar digestive problems and can cause acid reflux.
Timing is everything for the newbie Intermittent Faster, so make sure you’re planning it carefully and not ruining your work/sleep/training by being hungry/hangry.
Myths and Drawbacks
We’re going to start off by busting myths about Intermittent Fasting.
Intermittent Fasting has its benefits, but the way it’s been discussed is all hype until better evidence comes out: we’ve seen so much talk about the miracle benefits that it’s important to start by explaining why Intermittent Fasting is not the key to your diet!
Myth #1: Fasting CAUSES Fat Loss
This is just silly. If you’re fasting for 20 hours then eating 10,000 calories in 4 hours, you’re going to gain weight. You don’t get to eat like crap when you’re feeding just because you took time off!
Fasting can be a great way to help fat loss progress, but it’s not the fasting that causes you to lose weight. It’s all about the calories: if you’re fasting 20 hours a day, you’re going to be eating less calories than if you were eating constantly while you’re awake!
The fasting periods are all about cutting down on snacking and sticking to non-calorie foods. This means black coffee, green tea and sugar-free drinks. The first two have their own benefits, but the point is to keep yourself going without eating to sate your hunger: it’s tough, but its zero-calorie!
Feeding periods should be structured like any other diet: aiming to hit macros and calorie amounts that fit your goals.
While hucksters like Dr Jason Fung suggest that ‘calories don’t matter’, the reality is that calories are the ONLY reason you gain or lose weight. They’re the currency your body uses to buy muscle and sell fat – you can’t adjust your weight by fasting if you ignore calorie and macro quantities entirely – that’s the type of “intuitive eating” that got you out of shape in the first place!
Myth #2: Intermittent Fasting Fixes Insulin/Diabetes
This one is a really bad interpretation of the data – the kind of poor showing that science usually receives, being twisted to fit headlines!
Obviously, periods of fasting will reduce insulin levels because you’re not eating anything, but then when you eat all your calories in the space of 4-6 hours, you’re going to see huge spikes in insulin production afterwards! As you might expect, fasting reduces insulin but feasting/feeding shoots it right back up!
This is another Dr Fung-based misconception. The idea that short-term changes in insulin (those seen in response to 16-20hr fasting) make a big difference to diabetes risk are ridiculous! Insulin resistance is about long-term eating patterns, with daily eating habits playing very little effect when you take out the calorie and refined-carb intake.
Intermittent fasting can be a good tool for reducing your overall calorie intake if you tend to snack (on sugary junk, especially), but there’s very little research to suggest it has unique metabolic benefits that you wouldn’t get from just eating like less of an idiot!
Myth #3: Intermittent Fasting Protects Against Alzheimer’s
We wish this one was true: Alzheimer’s disease is top 10 cause of death in the world and a terrible condition. This makes it even more questionable that IF is being sold on misinformation about preventing Alzheimer’s disease and other brain conditions.
The studies that Fung cites in support of IF are performed on animals, which is a serious problem and invalidates a lot of the claims for intermittent fasting. Animal studies can be really useful when they’re good analogies for humans, but in brain disease they don’t hold up well.
First, these animals are often tested in long-term models of intermittent fasting. They didn’t decide to start fasting at 35 years old – they’ve been on IF their whole lives and have adapted. We need to consider what your body’s going to have to do to get used to the changes. Your body doesn’t do anything fast and these studies don’t relate well to IF as a diet, rather a lifelong lifestyle… of mice.
Second and most importantly, animal models don’t transfer well to human nutrition because of the huge differences in the size of mouse and human livers. Mice, the most common animal for study, have a much larger liver (relative to their body size), with a variety of benefits such as producing vitamin C internally, breaking down proteins into carbohydrates more effectively, and even producing ketones.
Ketone production and converting proteins into carbs are both key influences in brain health. This ability to handle brain-fuel sources internally means that the effects of intermittent fasting are not comparable in humans. We can’t break protein down into carbs as effectively or produce endogenous ketones as effectively – making IF studies on animals almost useless for brain disease!
This all sounds complicated but, basically, animal studies on IF and brain diseases don’t tell us anything about IF in humans. They’ve got a huge number of problems and they don’t give us definitive proof. It’s an interesting area of research but its going to be a while before there’s definitive proof either way!
Myth #4: Fasting Boosts Growth Hormone and Fat Burning
This is another silly rumour. The idea is that, by fasting, you can significantly increase your growth hormone output, which is tied to both muscle-building and fat loss. This is a huge deal because growth hormone is a key player in the recovery of things like joint tissue, too, so it benefits basically everything in your body.
Intermittent fasting has been praised by many “authority” sites (with a poor history of misrepresenting the literature) as having huge benefits to HGH production “up to 5-fold”. Their sources for this, however, show that HGH increases in the short-term (in response to whole-day fasting), but there were two major problems:
- The study admits that you can’t measure HGH levels effectively when not fasting because different macronutrients have important effects on HGH production
- The effects are short-term and, after this peak, HGH levels drop in response and are mediated by other hormones
These are key for the long-term effects. You’re going to see up to 8% better fat loss during this period, but it’s a short-term change and requires you to stop eating for a day. Beyond that, it’s going to drop your HGH levels afterwards to compensate, so it’s not really adding much to your diet in the long-term.
The other studies used to prove the benefits of IF for HGH/Fat-burning were based on biosynthetic HGH – injections of this anabolic steroid, rather than diet-based results. Clearly, you can’t compare the two!
Non-IF Diets ALSO Boost HGH!
It’s important to remember that your body produces HGH in response to a variety of dietary factors, above and beyond the short-term benefits seen in IF. For example, eating is an easy way to improve your short-term HGH – it’s not just not eating that helps!
Hypoglycaemia (low blood sugar) and other factors cause the boost in HGH seen in intermittent fasting. Aside from having negative side-effects of their own and being short-term, there are also a whole bunch of other ways to boost HGH:
- Serum arginine (from dietary arginine or L-Citrulline)
- Various vitamins (specifically B3)
Your diet can boost HGH without relying on fasting, fiddling with your blood sugar and risking side-effects (discussed below!). This is a real benefit, but the way that its been presented sucks: you’re not going to see appreciable long-term differences in your physique and you do risk short-term splitting headaches and fluctuations in your hormones.
Also, consider the possibility that higher levels of HGH aren’t always positive. Growth hormone levels in the body are related to negative effects on other compounds. High HGH levels can reduce insulin sensitivity and increase the long-term risk of diabetes – something we’ve already discussed as a serious risk.
Side-Effects to Fasting: Doing it Wrong
Fasting is a good, healthy choice for many people. However, it also brings its own risks that you won’t find in a regular diet, meaning it needs to be approached with an open mind and caution, rather than just running head-first into a 2-day fast!
As we mentioned above, you can quickly have problems with your digestive system if you’re trying to eat all your calories in one sitting. This is an easy way to overload your system, and it has a variety of different digestive risks if you’re missing anything in your diet.
Constipation is one possibility – you’re eating huge amounts of food at once and it’s totally possible that you’re not going to pass it all through comfortably! This is a real problem if you’re prone to constipation or you’re eating during a particularly-short window (such as 4hrs).
High fat diets combined with IF can cause the exact opposite of constipation. Eating high-fat foods within the space of 4 hours can cause serious diarrhea problems if you’re not careful. This can be changed slightly, but its going to be something you have to keep an eye on!
Additionally, high intakes of fat – especially saturated fat – during this time can be a contributor to things like colorectal cancer. Fats aren’t inherently unhealthy – some of them are amazing for your health – but too much at once places a real burden on your gut and can contribute to cancer risk in the area.
Watch out for acid reflux and other short-term digestive problems, too. We mentioned above that eating too close to bed can be a risk factor, but you can also suffer from acid reflux or IBS symptoms by simply eating too much too fast.
Not Eating: Sometimes it’s Bad for You!
For all the people claiming that they’re benefitting from intermittent fasting, there are real concerns about the negative effects they can have. These start with the fact that you’re not eating for almost a day at a time – this is going to cause low blood sugar for most people.
- Poor vision
- Brainfog or excessive fatigue
These are a real risk if you let them get too far. If you’re going to try intermittent fasting, you’ll have to keep an eye on these and consult your doctor just in case you run into any problems.
Fasting is only appropriate for some people (are you one of them? We’re going to let you know toward the end of this article) and your doctor needs to know if it’s going to be OK for you!
The REAL Benefits of Intermittent Fasting
For all the myth-busting we’ve discussed, Intermittent fasting does have some great benefits – we’re not haters!
We’re going to take you through the benefits of intermittent fasting and what you can benefit from, so that you know what’s real. These are the benefits that are going to make a difference to your diet and life, not just those that back up a product or ideology to sell (*cough*Fung*cough*).
Teach Yourself to Diet: Improving Dietary Quality and Control
One of the most important, personal development changes you can make with intermittent fasting is simply learning how to diet.
This sounds obscure – you’ve probably dieted before – right? The difference is that intermittent fasting teaches you how to avoid any form of unnecessary and avoidable snacking or “grazing”. If you’re the kind of person that eats healthily during meal time but spends the whole day eating junk, intermittent fasting is a great tool to combat bad habits.
This is the same as using Keto diets to reduce your sugar intake – it’s a way of learning to diet rather than being a perfect diet by itself. Remember that it’s a step in the right direction, even if it’s not a way to burn more fat – it teaches you the skills to build a perfect diet.
Better Blood: Improved Blood Lipid Profile
Intermittent fasting has some early research suggesting that it can actually improve the profile of your blood lipids – especially the cholesterol in your blood stream that contributes to long-term heart risk.
While the reason for this is still shrouded in a little bit of scientific mystery, there are many studies suggesting that fasting has modest benefits to cholesterol. This reduces your blood pressure and has a small effect on the overall risk of heart disease and other common causes of death.
It’s a modest benefit, but it can be worth a little time and effort – especially if you’re using IF as a method of improving your dietary quality and structure to start with. Extra perks are never bad, especially if they mean less risk of early, common causes of death!
Burning Dangerous Fat
One of the best benefits to intermittent fasting is the preferential burning of visceral fat. This sounds a bit dense, but it simply means that intermittent fasting helps your body to burn the fat around your organs at a greater rate (compared to superficial fat).
Visceral fat is worse for you than subcutaneous fat (the kind under the skin), placing pressure on the organs. IF can prioritize this type of fat, meaning that you’re going to see small improvements in your overall health (if you’re carrying lots of bodyfat).
This is more closely related to the type of exercise you perform and reducing your overall bodyfat (whether using IF or ‘normal’ diets) is a key way to manage your visceral fat. However, if you’re really worried about your health and need to lose this type of fat ASAP, intermittent fasting’s slim effect might be worth your time.
Autophagy: A Key Tool for Immortality?
One of the most exciting and over-hyped possibilities for intermittent fasting is autophagy. This is the way that cells consume waste and dead cells during periods of extended calorie restriction – they use up waste products to provide fuel.
This is basically the same as making the most of your leftover food in the cupboard when you’re too poor to buy anything new! It forces efficiency and a serious clean-up on the inside of your body, resulting in reduced waste products and, consequently, better health.
Autophagy is a relatively new concept in the scientific literature so we’re not sure just how effective this is going to be. Studies link overall lower calorie intake to longer life, independently of obesity, so it’s interesting to see whether this is going to be a key result for fasting as the science develops!
Reducing Muscle Loss When Cutting
This is a benefit that everyone wants: the early research (a common theme in fasting!) says that there might be benefits to muscle mass while cutting.
This one actually makes a lot of sense – nutrient timing is a small part of your diet’s overall effectiveness but using your fasting schedule properly can fuel your muscles while maintaining an overall calorie deficit to ensure that you’re losing weight.
Aim to have your major feeding window just after exercise to ensure that you’re providing your muscles with the necessary protein and carbohydrates to recover. This will mean you hang on to more strength and power while you cut, keeping your muscles primed and fueled without ruining your cut!
Resolving the Issue: What’s best for YOU?
The important question is this: will Intermittent Fasting work for you?
And that totally depends on who you are, what you’re looking to achieve and how your diet looks right now. We’re going to quickly outline who benefits from intermittent fasting and who should avoid it!
Who Can Benefit From Intermittent Fasting?
Intermittent fasting is an amazing gateway diet for the vast majority of people who are just getting into dieting after time off, or even a lifetime of just eating whatever they want. This is the main group for a number of reasons:
- It promotes a no-snack approach, cutting out a huge chunk of your daily calorie surplus
- It attacks visceral fat – the deep fat that is more harmful and more likely to be contributing to your health issues
- It’s an easy way to control your dieting: either you can eat right now or you can’t!
However, it’s important to remember that it’s only useful if you’ve already got your calorie deficit and macronutrient ratios planned out. Intermittent fasting won’t work if you’re eating loads of junk foods in a calorie surplus – it still relies on calorie intake!
Who should AVOID Intermittent Fasting?
There are certain populations who really should not be using intermittent fasting as a long-term strategy for health or weight control. This isn’t to say that its bad for everyone, but it does need to be measured against your lifestyle and exercise habits.
Athletes Should Not Use Intermittent Fasting
Intermittent fasting is a bad idea for athletes, who should be consuming food at a maximum of 6-hour intervals for recovery, muscle growth and performance indicators. These athletes need to be fueled constantly, especially during long days with multiple training sessions!
Auto-Immune Diseases and IBS
Intermittent fasting probably isn’t for you if you have a temperamental digestive system – if you’re easily constipated or you experience IBS, it’s a bad choice. The large amounts of food you consume during feeding blocks are going to back you up or irritate your system.
IF is a Real Diabetes Risk
Finally, it’s a bad idea for you if you’re using it as a band-aid to a bigger problem. Intermittent fasting is a pretty cool way of tweaking your diet to your needs but it can also be a way of masking the real problem with your diet.
If you’re just crap at sticking to your diet, intermittent fasting isn’t going to make you a better, more self-controlled person. You can use it as a tool to train self-restraint, but it won’t be a cure-all to your lack of willpower or love for twinkies!
The Bottom Line
We’re not skeptical of Intermittent Fasting itself – just the people who are trying to sell it to you at any cost! These people are more concerned with making a name for themselves than your long-term health and wellbeing!
Intermittent fasting is a great tool for learning how to control your dieting habits and easing into a more restrictive, self-controlled type of diet. It needs to be applied properly but, in fairness, so do all diets.
IF is a great way to structure your diet if you suck at snacking and find yourself “grazing” all day. It can also help you improve your cholesterol, combat visceral fat and may have benefits for long-term health and aging.
We like intermittent fasting for the groups mentioned above, it’s just important to remember that it won’t burn more calories than any other type of diet and it has to be related to your goals!
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Professional sport/fitness writer at ApexContent.org, weightlifter and S&C enthusiast. Liam has over 5 years experience in coaching positions, learning under the best mentors and sport coaches in Britain. At the same time developed a love for relentlessly researching and writing scientifically backed content in health, fitness and sport performance.
Liam wears many hats, but they’re unified by a love for competition, performance, and engaging writing. You can throw abuse (and questions) his way in the comments and he’ll be happy to help you!