Intermittent Fasting - Your guide to the benefits of intermittent fasting

Intermittent fasting is the little sibling of therapeutic fasting, which has been well-known since the 1970s.

While fasting describes an uninterrupted period of time in which you eat nothing at all, intermittent fasting (from the Latin intermittere – to interrupt) can be defined as a pattern of eating in which repeated, short periods of abstinence from food are alternated with periods of “normal” eating. It is usually characterised by fasts of 16 – 24 hours at a time or, alternatively, periods of eating with a heavily reduced calorie intake (depending on the method).

Intermittent fasting is known for its simplicity and flexibility and is therefore usually easier to implement than many other well-established diets. It is particularly ideal for people who lead busy lives because it makes everyday meal-planning a lot easier.

Overall, it is safe to assume that intermittent fasting is largely risk-free for healthy people. Most benefit from structuring their diet this way and attest to increased energy and resilience.

However, it can lead – especially in the beginning, when the body is still adapting to the adjustment – to side effects, although these usually subside quickly:

• Fatigue can increase significantly in the evenings but this can be a positive, because it leads to better sleep.
• Right at the beginning, dizziness and headaches can occur. We advise staying well hydrated to prevent this.
• In the first few days, food cravings and mood changes can arise, but these quickly disappear as soon as the body becomes accustomed to the new diet.
• For pregnant and breastfeeding women, as well as people suffering from an eating disorder, intermittent fasting is not an option.
• In the case of chronic illness a trusted doctor should be consulted first.

During intermittent fasting, you switch from a period of normal eating to a period of no food intake at all. The total lack of food during the fast naturally leads to an overall reduced calorie intake and thus has great potential to deliver weight loss results.

One of the great promises of intermittent fasting is the “cleansing” effect it is said to have in the body. Prolonged periods without solid food are likely to thank for this. Autophagy (the body’s process of recycling damaged cells) sets in after about 12 hours without energy intake and is the foundation for the numerous health benefits of fasting. Cells that have already been damaged are either renewed or destroyed by the body. It is important to note that this process can only occur when the body is no longer engaged in digestive processes.

In this way, intermittent fasting promotes weight loss and reduces the risk of some diseases, such as cancer or dementia. Animal testing has also demonstrated further benefits, including a longer life expectancy, healthier blood pressure and a lower incidence of age-related diseases, along with a lower susceptibility to bacterial infections.

A large proportion of findings from animal testing cannot be directly applied to humans, but they can often indicate a trend.

The frequent switch between periods of low or no food availability and phases of sufficient food supply, which characterised the daily life of our early ancestors, is beneficial for our health and boosts our resilience overall.

There is really very little you can do wrong. However, it wouldn’t do any harm take a look at the following tips and tricks for a brief how-to on intermittent fasting. If you take note of these few points, nothing can stand in your way!

• Take it easy: make changes to your diet in gradual steps

If you find it difficult at first, your stomach is relentlessly rumbling, and you’re having trouble falling asleep, increase the number of hours you go without food slowly but steadily.  

• Listen to your nutritional instinct and find your own routine

Find out what routine you like best. Don’t want to skip breakfast? Start your eating phase in the morning and begin your fast in the afternoon. Prefer dinner? Skip your morning meal and start fasting late in the evening, after dinner.

• Concentrate on what is good for you

Your body is not a machine. Give it enough time to come to terms with the change. You will soon adapt completely and feel great in no time!

• Avoid stress as much as possible

In order to give your body the chance to adapt, you should, especially during periods of fasting, allow yourself to rest. So try not to subject yourself to unnecessary stress.

• Eating a healthy and balanced diet is essential

Even if intermittent fasting is relatively flexible, you should of course not spend your free-eating period consuming junk food and soft drinks endlessly. Upfit’s personalised meal plans for intermittent fasting can help you maintain a healthy and balanced diet. Don’t forget to drink plenty of water. Unsweetened tea and black coffee are also permitted during fasts.

• Don’t let exceptions drive you crazy

Once in a while, you might decide to go out for that dinner with your friends or break your fast earlier in the day because you’re feeling particularly hungry. Don’t panic. Exceptions – as long as they remain exceptions – will not block the path to your dream figure.

There are several different approaches to the structure of intermittent fasting. We introduce you to the three most popular methods: alternate-day fasting (ADF), the 16:8 diet and the 5:2 diet. They may seem complex at first, but once understood, they are relatively easy to put into practice.

Probably the most well-known form of intermittent fasting, alternate-day fasting, is an alternation between one day of normal eating and one day of eating nothing at all. During the fasting day, only water, unsweetened tea and coffee are allowed.

• ADF is feasible for anyone with good health and self-discipline.
• This diet is mainly for people who want to lose weight.
• It is especially suitable for those who like exercising and want to lose body fat, but are not focused on building muscle.
• The ADF diet is very practicable for people who lack self-discipline, as postponing or swapping phases around is not possible.

If you still have trouble finding the motivation to make changes, take a look at our Motivation Guide to get some valuable and helpful tips.

ADF should allow you to shed those pounds without having to worry too much. If you also choose to avoid sugary foods during the eating phases and make sure you eat a lot of vegetables and high-quality protein (e.g. lean meat), the process will be accelerated and you will lose less muscle mass. Another way to maintain muscle mass and still reap the benefits of fasting is to have 3 protein shakes on each fasting day (each consisting of about 30g of protein powder in 300ml of water – preferably vegan protein like rice, pea or hemp in any flavour you like). An unbalanced diet with lots of carbohydrates (bread, pasta, potatoes, etc.) and few vegetables is not recommended.

Deficiencies can quickly arise due to a low intake of important micronutrients, such as vitamins and minerals. Ultimately, fasting is not a substitute for a healthy diet. The Upfit Nutrition Guide for Healthy Eating can tell you all about how to eat a healthy diet.

The 5:2 diet does not involve a proper fasting period. Instead, each week is divided into 5 days when you can eat normally and 2 days on each of which women can eat a maximum of 500 kcal and men 600 kcal. These calories should be spread out over one or two small meals of vegetables and protein.

• This diet can be practised by anyone with good health and self-discipline.
• If you’re struggling with the idea of ​​not eating for a whole day and are a serial snacker, 5:2 is for you.
• You should set yourself fixed “fasting” days for every week (e.g. Monday and Thursday), so that this new way of eating becomes habitual.
• Don’t betray yourself and your goals – there are no official guidelines on what you should eat, but be sensible!
• The 5:2 diet is ideal if you want to do a lot of intensive exercise during the 5 eating days.
• It is also suitable for the long term and can be implemented as a permanent change.

The 5:2 diet is a fairly flexible variation of intermittent fasting that promotes weight loss and allows for intensive exercise. However, this can only really be successful under a few conditions: firstly, it is advisable to have your “fasting” days on the same days of each week, and secondly, the diet on the “normal” days should also be adjusted to include lots of vegetables, lean protein sources and little sugar. When it comes to exercise, it makes sense to use the fasting days as rest days.

Reports on the 5:2 diet show that reducing the amount of calories on fasting days is more difficult for many than not eating altogether. Reports of torturous cravings are not uncommon. It is all the more important to cover your permitted calories with foods with a low energy density (salad, vegetables, some lean meat) and to drink a lot.

The 16:8 diet does not work on a day-to-day basis, but on an hour-to-hour basis instead: each day, you can eat normally within an 8 hour period, while for the remaining 16 hours you are only allowed water, coffee and unsweetened tea. At first glance, this seems to be a very easy pattern to implement, since the time you are asleep counts towards the total fasting time for each day. Typically, eating times are between 8 a.m. and 4 p.m. (where dinner is omitted), 10 a.m. and 6 p.m. (compressed day), or 12 p.m. and 8 p.m. (where breakfast is omitted).

You can therefore adjust the start and end of the eating phase flexibly according to your eating habits and daily routine. But beware: since it is important to get used to this new habit, the 16/8 method should be thoroughly stuck to – even on weekends and public holidays. For many, this can be a problem, because spontaneity is also severely restricted.

In contrast to the other two methods presented, the calorie intake hardly changes during the free meal times. However, the long break between the eating phases definitely delivers results if you want to achieve and maintain your ideal weight and good health. Of course, even with the positive effects of intermittent fasting, you will be treading water if you only eat junk food and sweets.

• This type of diet is also feasible for anyone who is healthy and self-disciplined.
• The 16:8 method is particularly suitable for those who are better able to cope with small but regular changes and prefer to have a permanent routine.
• People who have an inconsistent sleep schedule or travel a lot/for long periods of time will have problems.
• People who have trouble resisting small snacks in addition to large meals will celebrate good success with this method.
• However, people who are used to eating many small meals throughout the day will find it difficult to cope with the small time constraint.

You can leave most of the organisation to Upfit – we’ll create your perfectly tailored meal plan and save you a lot of time. By taking your individual preferences into account, we can help make intermittent fasting work for you.

Once you’ve reached the weight you were aiming for, a few exceptions to the 16:8 structure can be made now and again, as long as they’re rare. In terms of both exercise and mental well-being (e.g. struggling with hunger or perseverance), there are no limitations to this method, which is why it is absolutely suitable for long-term nutrition.

Is weight loss your goal? Intermittent fasting has proven itself as an effective method time and again, and many people have already had success with it. Because of its effects on the body, intermittent fasting is primarily used as a tool to achieve an ideal weight. Switching to intermittent fasting is very easy to do as there are few restrictions during “eating times”. The fact that it works for most people despite this makes it an exciting approach to losing weight (and subsequently maintaining your new, lower weight).

Avoiding certain dishes while fasting automatically reduces your calorie intake. In this way, the number of calories you burn outweighs the calories you require to maintain your current weight, and thus leads to weight loss.

If you want to learn more about how many calories you need per day, feel free to use our calorie calculator.

It is recommended that most skip breakfast and start with lunch as their first meal of the day. If you then consistently leave your daily carbohydrate intake until dinner time, your leptin level throughout the entire day should increase, as studies have shown. Leptin is the hormone responsible for feeling full, so this allows you to avoid those pesky hunger pangs. With leptin’s help, it is very easy to maintain this diet permanently, especially if you want to lose weight first. The phase of heightened fat burning, which occurs after about 10 – 13 hours of fasting, remains unaffected by the lack of hunger.

Furthermore, when carried out correctly, you should not fall victim to the dreaded yo-yo effect after your desired weight loss has been accomplished, since your metabolism will not shut down and muscles are not broken down.

If you are striving for weight loss, but don’t want to give up certain foods and enjoy following a routine, you will achieve your goals with intermittent fasting. Upfit’s personalised meal plans can make all of this possible for you! We are more than happy to help if you want to slim down with intermittent fasting.

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2. Dohm, G. L., Beeker, R. T., Israel, R. G., Tapscott, E. B. (1985): ‘Metabolic responses to exercise after fasting’. In J Appl Physiol, 61 (4), pp. 1363–1368.
3. Zimmet, P., Thomas, C. R. (2003): ‘Genotype, obesity and cardiovascular disease – has technical and social advancement outstripped evolution?’. In J Intern Med., 254, pp. 114–125.
4. https://en.wikipedia.org/wiki/Intermittent_fasting