General
What is this based on, medically and scientifically?
Hundreds of scientific studies have been published that examine the effect of intermittent fasting on body weight and risk factors for disease. Results from these studies show that intermittent fasting can help people lose weight and reduce belly fat while maintaining the majority of their muscle mass. These diets have also been shown to lower heart disease risk by reducing ‘bad’ cholesterol levels and blood pressure, while increasing ‘good’ cholesterol levels. Intermittent fasting may also be protective against diabetes by lowering insulin and insulin resistance. As if that wasn’t enough, these diets have also been shown to improve brain function and lower the risk for Alzheimer’s disease. To read more about the science and medicine behind SuperFastDiet, click here.
What is SuperFastDiet (SFD)?
SuperFastDiet is an intermittent fasting weight loss program where you have the option to choose from a number of different intermittent fasting options. Generally, these consist of either two, three or partial ‘fast days’ where you eat less than you normally would, restricting your calorie intake to either a quarter, half or 80% of your Total Daily Energy Expenditure (TDEE) which is designed to achieve a weekly 20% calorie deficit. These ‘fast days’ are alternated with either five, four or partial ‘non-fast days’ (or ‘feast days’) where you eat normally. Recent studies show that people can lose between 0.5kg – 1kg per week using this method.
What is intermittent fasting?
Intermittent fasting involves a period of not eating (or ‘fasting’) followed by a period of eating freely. There are several forms of intermittent fasting to choose from, including the 5:2 diet (aka 2 Day Fast), alternate day fasting (ADF), the 4:3 diet (aka 3 Day Fast) and the 16:8 diet (aka Part Day Fast). The 5:2 diet involves 2 days of fasting per week, where you lower to your calorie intake to 500 calories per day (or a quarter of your TDEE). On the other 5 days, you can eat normally, without having to count calories or monitor food intake. Alternate day fasting takes it one step further by adding a couple more fast days per week. More specifically, with alternate day fasting, you alternate between a 500-calorie fast day and a normal eating day, every other day. You can eat the meal all in one go or split it up in to mini meals. The 4:3 diet involves 3 days of fasting per week, where you lower your calorie intake to 1000 calories per day (or half of your TDEE. On the other four days, you can eat normally. The 16:8 diet (or Part Day Fast), is a little different from 5:2, 4:3 and alternate day fasting in that you fast a little bit every day. With 16:8 you are free to eat during an 8-hour window (let’s say 10am-6pm) then you would fast the rest of the day (6pm-10am). You can choose whatever 8-hour window works for you.
Will I be malnourished on a fast day?
As long as you are eating nutritious food this will not be a concern, however, you may want to consider taking multivitamins if in doubt. If you are worried about not getting the recommended intakes of vitamins or minerals while doing intermittent fasting, we would strongly suggest taking a multivitamin/mineral supplement on both fast days and non-fast days. Keep in mind that vitamins and minerals are calorie-free, so they will not count towards your calorie allowance on fast day. Please only take the recommended dosage indicated on the bottle, and only take iron supplements if recommended by your doctor.
What is TDEE?
TDEE stands for Total Daily Energy Expenditure. It’s a way of calculating how many calories you burn each day, just by how you live, what you do and what your activity level is. Calculating your TDEE will help you ensure that you’re eating the right number of calories on both fast days and non-fast days.
Is my TDEE worked out by my activity level over a day or a week?
It’s worked out as an average activity level over the space of a week. And it’s better to underestimate than to overestimate. For example, if you spend most of the day sitting down, but you exercise a little, opt for ‘Sedentary’ rather than ‘Light Activity’ and you’ll get the best result for optimum weight loss.
How long does it take to adjust to this eating pattern?
It takes about 1-2 weeks to adjust to intermittent fasting. Most people report hunger and irritability during the first couple weeks, but this subsides quickly. Try your best to not give up on the diet during this initial period… it WILL get a lot easier!
What sets SFD apart from other diets?
One of the things people like best about this diet is the freedom to eat whatever they want on non-fast days. The ability to feel normal (not deprived) every other day may also help people stick to SFD for longer than daily calorie restriction. So, feel free to enjoy the foods you love on non-fast days!
Do I need to count calories on the non-fast day?
Yes. At least to start with. Once you get used to eating the right amount for your TDEE (total daily energy expenditure), you’ll be able to ease up on counting, but it’s a good idea to count calories even on your non-fast day so that you can ensure you’re not going overboard, especially in the early stages.
Can SuperFastDiet be used to lose a small amount of weight (2-5kg)?
Yes. In a recent study, scientists showed that normal weight and slightly overweight people can use the diet to drop the last 2-5kg, and achieve their ideal weight. Just keep in mind that as you are close to your ideal weight, your weight loss will likely be quite slow (about 0.45kg per week). To speed up the weight loss, you may choose to add in an extra fast day, or some extra exercise sessions each week.
What is BMI?
BMI stands for Body Mass Index. It’s a widely used way of calculating the optimum weight range for your height. BMI is calculated by dividing your weight in kilograms by your height in metres squared. It can help give you an idea of whether your weight is in the ‘Healthy’, ‘Under Weight’, ‘Overweight’ or ‘Obese’ range. Keep in mind that BMI is a guide only, and does not take into account age, ethnicity, body type, gender or body composition. BMI should not be used by those under 18, athletes or to calculate healthy weight for pregnant women. We recommend pairing your BMI with other measures such as waist circumference, body fat percentage and having your doctor check other risk factors as well. According to the National Health and Medical Research Council, a BMI of 20-25 is considered healthy for most adults.
How can the SuperFastDiet result in weight loss, when it allows me to eat normally most days?
Our research shows that people don't (or maybe even can't) binge on the non-fast day. The two day fast is equivalent to 25% of a person’s energy needs, the three day fast is equivalent to 50% of a person’s energy needs and the partial day fast is equivalent to 80% of a person’s energy needs. Essentially, they all result in the same outcome: a reduction in your weekly calorie intake by around 20%. When scientists first started studying this diet, they assumed that people would eat 175% or 150% of their calories on the non-fast day, to fully compensate for eating only 25% or 50% of their calories on the fast days. This isn't the case though. Recent findings show that people only eat about 110% of their daily calories on the feast day, instead of the predicted 175%. Why is this? They don't fully know, but it’s presumed that it involves stomach shrinking, or an increased sensitivity to fullness signals. Studies are currently underway to find out what is responsible for this effect.
Can I drink alcohol during this diet?
Yes, it's fine if you drink alcohol on your non-fast days. However, we generally advise against consuming alcohol on the fast day since 1-2 drinks may account for your entire 500-1000 calorie allowance on that day. Since alcohol is completely deficient in nutrients, it's much better to eat actual food on the fast day.
Is it better to eat a high protein diet while I’m on SuperFastDiet?
At this point, scientists have only examined whether the diet works when eating high fat foods. Results from this high fat study indicate that people can lose just as much weight while eating high fat foods on fast days and non-fast days, as compared to eating low fat foods on these days. Whether these same effects are noted with a low glycemic diet or high protein diet, have not yet been tested, but scientists hope to study this soon.
How Do I Cancel or Unsubscribe?
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Safety & Medical Disclaimer
Do I need to worry about nutritional deficiencies while doing intermittent fasting?
As long as you are eating nutritious food this will not be a concern; however, feel free to consider taking a multivitamin, if in doubt. Please remember to only take the recommended dosage as indicated on the bottle, and to check with your doctor if you have any concerns. And only take an iron supplement if it’s recommended by your doctor.
Is intermittent fasting safe?
Approximately 50 studies of intermittent fasting have been performed in rodents, and about 30 studies have been performed in humans. Of these studies, only one to date has reported negative effects of intermittent fasting (in rodents only). Studies in humans routinely demonstrate heart-healthy benefits of intermittent fasting, such as drops in cholesterol, blood pressure, glucose and improvements in insulin sensitivity.
Is it normal to get headaches on the fast day?
Headaches on the fast day are most likely due to dehydration. Since you are only eating 500 calories, you are getting much less water from food sources on diet day. As such, please be sure to drink an additional 8-10 glasses of water/clear liquids on diet days, and the headaches should clear up. Please contact your doctor if the headaches persist.
Is intermittent fasting safe for diabetics?
Recent studies indicate that intermittent fasting can help lower fasting glucose, insulin and overall insulin resistance in obese individuals with pre-diabetes. Studies will be conducted soon to see if these improvements also occur in type 2 diabetics. If you have type 2 diabetes, and would like to try intermittent fasting, we would advise speaking with your physician before starting the diet. We do not recommend intermittent fasting for type 1 diabetics. Long or moderate durations of fasting could potentially be very dangerous in this group of individuals. Important note: If you have any medical conditions or are taking prescription medication of any kind for any condition at all, we highly recommend speaking with your physician prior to commencing any new diet, eating or exercise regime.
Who should not do SuperFastDiet or Intermittent Fasting?
We do not recommend SuperFastDiet or Intermittent Fasting if:
- You’re pregnant, planning to get pregnant or breastfeeding
- You have an eating disorder, a predisposition to, or a history of eating disorders
- You have a BMI of below 20 or you’re underweight
- You have medically diagnosed hormonal issues
- You have been diagnosed with Type 1 Diabetes
- You are younger than 18
- You are older than 70 (unless first seeking doctor’s advice)
Why do I feel cold on fast days?
In general, people feel cold while losing weight for a couple of reasons:
1. you are losing fat (which acts as insulation against the cold) 2. since you are consuming a restricted amount of calories, your body may be using less calories to keep you warm, and more calories to keep other important body functions running.
Hormonal issues while intermittent fasting?
Intermittent fasting has not been shown to cause hormonal imbalances or fertility issues in adult women. In fact, subjects participating in Dr. Varady’s studies have reported that losing weight with intermittent fasting has actually helped them become pregnant and improve the regularity of their menstrual cycles. This myth seems to have originated with a study that was published a few years ago, which showed that normal weight teenage female rats developed hormonal imbalances after water fasting every other day. However, it’s important to note that these young lean rats lost almost a quarter of their body weight during a critical developmental stage (puberty). Losing extreme amounts of weight during puberty with intermittent fasting is not recommended as it may impede growth and lead to reproductive issues. That’s why we don’t recommend intermittent fasting for anyone under 18. Important note: If you have any medical conditions or are taking prescription medication of any kind for any condition at all, we highly recommend speaking with your physician prior to commencing any new diet, eating or exercise regime.
Amenorrhea or irregular periods while intermittent fasting?
Intermittent fasting does not result in amenorrhea or irregular periods. Hundreds of women have participated in intermittent fasting studies and neither of these adverse effects has ever been reported. However, amenorrhea or irregular periods can occur if you lose too much body fat and drop below a body mass index (BMI) of 18.5. You can check to see if you are staying within the healthy BMI range by using this handy calculator. Important note: If you have any medical conditions or are taking prescription medication of any kind for any condition at all, we highly recommend speaking with your physician prior to commencing any new diet, eating or exercise regime.
Medical Disclaimer
SuperFastDiet contains general information about dieting, nutrition and health. It is not to be treated as medical advice. The medical information in this book is provided without any representations or warranties, express or implied.
Before starting any diet, seek professional medical advice from your doctor.
This diet is not recommended for the following:
- Women who are pregnant, planning to get pregnant or breastfeeding
- Anyone with an eating disorder, a history of or a predisposition to eating disorders
- Those with a BMI of below 20 or people who are underweight
- Anyone who has been diagnosed with Type 1 Diabetes
- People younger than 18 years old
- People older than 70, without doctor's permission
Important note: If you have any medical conditions or are taking prescription medication of any kind for any condition at all, we highly recommend speaking with your physician prior to commencing any new diet, eating or exercise regime.
Fasting
Will I be hangry all the time?
The short answer is: yes, you will be hangry, but no, not all of the time. Although chances are you will be hangry or irritable, at least a little for the first few weeks, until you get used to the diet. But this subsides fairly quickly. Also, it’s worth remembering that studies have shown hunger doesn’t actually get worse over time. It does hit a peak, but then it starts to subside again. Once you get used to the new way of eating, you’ll come to look forward to fast days and the energy boost that they bring. Seriously!
How can I suppress hunger on the fast day?
- Eat high fibre foods for your fast day meal (nuts, beans, fruits and vegetables) or chew high fibre gummies
- Eat high protein foods for your fast day meal (meat, fish, tofu, or nuts)
- Drinks lots of water. People tend to think they're hungry, when they are really just thirsty.
- Drink black coffee/tea, or cinnamon/licorice herbal teas. All of these beverages have appetite-suppressing effects.
- Watch less TV! We know this sounds strange, but while you are watching TV, you are bombarded with dozens of ads for food. This can make you feel hungry, when in actuality, you are not hungry at all.
- If you’re still struggling, check out our blog for loads of Distracting and Worthwhile Things To Do When You’re Hungry.
When should I eat the fast day meal?
Most individuals prefer to have the meal as a lunch or dinner, but you can do whatever works for you.
Can I break up the fast-day meal into smaller meals?
Yes. Scientists recently completed a study that suggests that people can split up the 500 or 100-calorie meal into 100-200-calorie meals throughout the day, and see the same weight loss results as consuming the meal all at once.
Can you give an example of a 500-calorie meal for the fast day?
We would recommend 50-80 grams of protein and plenty of non-starchy vegetables on the fast day. Salad with chicken is a great option. This meal is filling, it takes a while to eat, and it's high in protein, fibre, vitamins and minerals. Just make sure you measure out your dressing! Salad dressings are sneaky high-calorie foods. If you're not into chicken, tuna is also a great option as this food is almost 100% protein. Download recipes for each method here!
Where can I find fast day recipes?
There are hundreds of low calorie recipes available in the recipe section of our program, as well as more available in the SuperFastDiet book!
Can I switch my fast days around?
It's completely fine to occasionally switch your fast days around, if it doesn't throw your weight loss off-course. For instance, if you have a social outing on Saturday, and that happens to be your fast day, it's fine to push the fast day back to Sunday. However, just be aware that some people find it difficult to have two fast days back-to-back. Most people find it easy, to start with, to opt for Monday and Wednesday, or Monday and Thursday as their two fast days. Alternatively, if you’re fasting for three days, you can do Sunday, Tuesday and Thursday, or Monday, Wednesday and Friday. Find what works for you.
Can I break the fast and enjoy the eating normally immediately after midnight?
Although the non-fast day technically starts at midnight, we generally recommend that people wait until they wake up to start eating. In this way, your body will benefit from the extended fasting period (in terms of weight loss and heart disease risk reduction).
Is it okay to not consume any calories on the fast day?
In general, we don’t recommend doing a complete fast on fast day because we’ve found it can be very difficult to get through the day. Two short-term studies (2-3 weeks) have tested ‘true’ fasting diets on health outcomes, and dropout rates were very high. Subjects quit the diet because they felt very irritable, constantly hungry, and were not able to concentrate at work. However, the subjects did lose weight (2.3kg), and cholesterol levels decreased. On the other hand, if you find it easier to do SFD by completely fasting on fast day, feel free to do so.
Can I use juicing as my fast day nutrition?
We recommend that you consume foods high in protein on the fast day, to help stave off hunger. Juice is very high in sugar, and very low in protein, so we wouldn't advise only consuming juice on the fast day.
How can I handle holiday eating while doing SFD/intermittent fasting?
Go easy on yourself during the holidays. If a holiday dinner falls on a fast day, feel free to eat what you want. Missing 2-3 fast days per month will not have a tremendous impact on your weight loss, so feel free to let loose every now and then. That’s the beauty of SuperFastDiet! Eat, drink and be merry, for tomorrow, you can fast! Read more here!
Why do I get strange dreams while fasting?
Lots of people report changes in sleep habits when they start fasting. Most commonly, fasters report sleeping more deeply and having more vivid dreams at night. The effects of fasting on sleep quality and duration have only been studied in two trials to date. Most recently, it was shown that time restricted feeding (limiting the eating window to 10 hours per day, and water fasting the rest of the time) improved sleep quality in overweight men and women. Another study showed that fasting for one week (while consuming 300 calories per day) improved overall sleep quality while boosting daytime concentration. This study also reported mild increases in REM sleep. REM is the sleep stage where we experience our most vivid dreams, so this could explain why some people experience very lucid dreams on fast days.
Exercise
Can I exercise on the fast day?
Yes. However, you may find it difficult to exercise during the first week or two of the diet. We recommend letting your body adjust to the SFD eating pattern for 2 weeks, and then start (or restart) your exercise regimen.
Does it matter if I exercise before or after the fast day meal?
We strongly recommend exercising before the meal on your fast day. People tend to have a hunger surge about 40 minutes after exercising. Thus, if you exercise before your meal, you will have that meal in place to satisfy your hunger. In contrast, if you exercise after your meal, you may be more likely to eat another meal on the fast day to sooth the hunger surge.
Can I use exercise on the fast day to earn more calories?
Technically, you can, but we don’t recommend it. People tend to grossly overestimate the number of calories they burn while exercising. This happens because most exercise machines overestimate calories burned by 50-100%. For instance, a typical elliptical machine will tell you that you've burned 300-400 calories in 30 minutes, when in actuality, most people will only burn 100-200 calories. Because of this overestimation, people often leave the gym thinking they can eat a 400-calorie snack. However, if they do this (when they've only truly burned 150 calories), they will be eating 250 calories more for the day, completely negating the effect of the exercise!
Metabolism
Does fasting decrease muscle mass?
In general, when someone is losing weight using traditional calorie restriction, they lose 25% of weight as muscle and the remaining 75% as fat. Recent findings show that this ratio is altered with intermittent fasting. During an intermittent fasting regime, most subjects only lose 10% of weight as muscle and 90% as fat. Thus, this diet may help to retain muscle mass, which can help to keep your metabolism high.
Is it normal to see 0.5-1.5kg weight gain in a 24-hour period?
Yes. It's typical for a person's weight to fluctuate by 0.5-1.5kg each day. These changes occur because of daily water retention and the weight of the food in your gut. For most accurate results, weigh yourself in the morning before eating or drinking anything. As long as you are seeing consistent weight loss week to week, there is no need to be worried.
Should I keep the calories up on non-fast days in order for metabolism to not slow down?
Unfortunately, all weight loss diets lower your metabolism by 10-15% when you reduce your body weight by 10% or more. This occurs with both daily calorie restriction and intermittent fasting. The only way to prevent this drop in metabolic rate is to exercise 5 times per week for 45 min/session (which increases your muscle mass). Since your muscle mass is a key determinant of your metabolic rate, increasing muscle mass will ensure your metabolism stays high, even post-weight loss.
Does metabolism return to normal once your weight has been stable for 6 months after weight loss?
The short answer is, unfortunately, no. To explain this, let’s use some examples: Let's say "Person A" weighs 65kg (5’6” height) for their entire adult life and has a metabolic rate of 2000 calories per day. "Person B", on the other hand, lost 22kg over the past year, and now weighs 65kg (5'6” height). You would assume that this person would now have the same metabolic rate as "Person A" (2000 calories per day). This is not the case, however. The person that lost the weight would have a metabolic rate 10-15% lower (about 1800 calories per day) than the person who was weight stable all of their adult life. Whether or not the metabolic rate of the person who lost the weight would slowly creep up to 2000 calories per day, over the next few years, is not known.
Will weight loss during SFD reach a plateau after several months?
Yes, some people have experienced weight loss plateaus after 4-6 months of intermittent fasting. This also occurs in people that are in the range of normal weight. If this is happening to you, we recommend adding another fast day to your week (resulting in 3 fast days in a row), as well as another exercise session (45 min). This has helped most people break through the plateau.
Do our bodies really have a set point weight?
The ‘set point theory’ suggests that the body strives to maintain a specific preset weight, and as such, when you lose weight, your body will try to gain it back. Although this theory is fairly well known, there is no convincing evidence to show that a ‘weight set point’ actually exists. The main reason that people gain back the weight they have lost is because their metabolism has decreased.
I thought I was supposed to have 5 small meals a day?
The concept of eating five small meals a day has been linked to boosting metabolism, but there’s actually no scientific basis for this. In fact, not only does it not rev up your metabolism, but it could actually cause over-eating, especially as many people have trouble keeping their portions in check. People who do lose weight using this method aren’t experiencing a boost in metabolism, but rather are curbing their cravings and preventing grazing. That’s what leads to weight loss, not an increase in metabolism.
Won’t skipping breakfast slow my metabolism down?
While this has been drilled into us by the media, our mothers and big breakfast cereal corporations, there’s actually no scientific evidence that breakfast boosts your metabolism. What it does do (as does all food) is offer what’s known as the ‘thermic effect’ of food, which is where your body expends calories in order to break down whatever you’ve just eaten. However, this only accounts for a small boost, around 10-15% of total metabolism, and any meal will offer the same benefit.
If I go into starvation mode, won’t my body hold onto fat?
It’s well established that long periods without food will cause a drop in metabolism, and while starvation mode or ‘adaptive thermogenesis’ does exist, it’s actually much harder to achieve than most people would have you believe. Your body will only go into starvation mode if you severely restrict your calorie intake over a long period of time. Your body is designed to first burn the energy you’ve eaten, then to burn glucose stores and then to burn fat. You will not go into ‘starvation mode’ until your body has depleted its stores of fat. Studies have shown that long periods of very low-calorie diets are far likelier to induce a drop in metabolism than intermittent fasting. In fact, recent studies report that fasting for short periods can actually increase your metabolism, rather than slowing it down. One study showed an impressive 14% increase in metabolism during intermittent fasting. This increase is thought to be partially due to an increase in norepinephrine, which is a hormone that promotes fat burning. You’ll find more on the myth of metabolism here.