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Fasting for weight loss – the nutritionist’s guide

Fasting for weight loss - the nutritionist's guide MAIN

Fasting for weight loss is now a well-known fact in the world of nutrition. But fasting has more than just weight loss benefits – Nutritionist May Simpkin shares a guide on intermittent fasting

We’re always told breakfast is the most important meal of the day.

But is it really? There’s actually plenty of research pointing to the benefits of skipping breakfast and following an intermittent fasting regime.

Fasting has been used for thousands of years

This isn’t news to nutritionist May Simpkin, who says the benefits of restricting calories on health and extending life span are well established.

‘Fasting has been used for thousands of years for spiritual and health benefits and has become popular in recent times due to the celebrity endorsement of intermittent fasting, aka the 5:2 diet,’ explains Simpkin.

‘Although dietary advice has long focused on eating regular low-fat meals, Intermittent Fasting (IF) and the 5:2’s counterintuitive approach to weight loss has attracted thousands of women and men.’

May Simpkin outlines the different benefits…

Benefit #1 It helps aid weight loss

Weight loss tends to be the most common reason for intermittent fasting. This fasting approach works on the notion of restricting your energy intake to certain times and in doing so, the research suggests it to be an effective way to lose body fat.

After a meal, the digestive system processes the food you have just eaten; digesting and absorbing, so that the body can use the nutrients the food has provided.

This process takes around four to five hours, during which time the body will prioritise using the carbohydrates provided as part of this meal as its preferred energy source, rather than rely on fat stored in the body.

Following a meal, insulin levels will be high and when insulin levels are high, the body is less likely to use fat as fuel. However, after this point, the body will need to use its fat stores as a source of energy, which will result in weight loss.

READ MORE: I lost over two stone on the fasting-mimicking diet

weight loss, why fasting works if you're looking to lose weight by healthista

Benefit #2 It can improve glucose tolerance

Insulin resistance is generally caused as a result of the body’s reduced ability to remove excess glucose from the blood either because insufficient insulin is released or the glucose receptors have become less sensitive.

Excess glucose will be converted to fat and stored in tissues not suitable for fat storage. As the body uses fat as a fuel during intermittent fasting, fat stores will reduce allowing the cells to regain insulin function and glucose sensitivity.

Having a regular routine, with strict eating times, can simplify your day to day life

Studies show that IF can improve many health parameters especially in pre-diabetic and insulin resistant people, where a caloric restriction can avoid the need to use medication.

Further findings also suggest that short term intermittent fasting may be a safe and tolerable dietary intervention for those already diagnosed with Type 2 Diabetes and may improve body weight and fasting glucose levels.

Benefit #3 It can help you look younger

Researcher Dr Rozalyn Anderson made the bold claim that people are often unaware of the ‘amazing fact’ that wrinkles are inevitable in the most recent edition of The Journal of Gerontology. And it only comes down to calorie restriction, according to growing evidence.

One landmark study earlier this year that showed adults age 0.6 years slower if they eat 25 per cent less calories each day – roughly 1875 for men and 1,500 for women.

adults age 0.6 years slower if they eat 25 per cent less calories each day

‘One of the things that people sometimes miss is the amazing fact that aging can be altered; caloric restriction research proves this’, said Dr Anderson, who was also behind promising research in January that revealed fasting in middle age can help people to live longer.

‘By reducing calories, the body is able to use energy from food differently, become more resilient, and ‘instead of fighting cancer or cardiovascular disease individually, target the full spectrum of disease simultaneously’.

Benefit #4 It helps to establish a routine

Although it can be difficult to establish a new way of eating in conjunction with family or work commitments at the outset, once you’ve developed a plan that works, tweaking and adjusting to suit your lifestyle, it’ll soon simply become the way you eat, in terms of timings and good quality meal choices.

Understanding your body’s genuine hunger signals and not confusing them with cravings often associated with the consumption of too many processed foods will give you greater understanding of your body and improve your confidence to maintain healthy habits.

Having a regular routine, with strict eating times, can simplify your day to day life especially if you’re feeling good for it.

READ MORE: ‘Ditch FAD diets’ says Dr Michael Mosley – plus 7 healthy recipes for the New Year

clock vegetables, why fasting works for weight loss by healthista

Benefit #5 It improves your skin health

Many skin conditions can be alleviated by eating a good quality diet, high in vegetables and fibre and avoiding processed foods.

To ensure adequate nutrients with IF, you will need to avoid these pro-inflammatory foods that offer little nutritive value and in doing so, you will reduce inflammation, often associated with skin conditions such as acne and eczema.

Many skin conditions can be alleviated by eating a good quality diet

Furthermore, if you suspect your skin condition is exacerbated by a specific food sensitivity or intolerance, eliminating this food during a fast will offer you the opportunity to re-introduce a food one at a time afterwards, to establish if it is the culprit.

Benefit #6 It makes you more resistance to health conditions

Intermittent Fasting’s ability to reduce weight will result in lower body fat. This has further benefits to many health outcomes including improving heart function, helping to prevent cancer and generally improved immune health.

Benefit #7 It will help you focus

Being in control of regulating your food intake also makes you more aware of your body. This deepened sense of understanding and connection can help reduce stress and anxiety and allow you to have a clear mind to focus.

READ MORE: Boost immunity in just 10 minutes with these 5 simple breathing exercises

heart function doctor, why fasting works for weight loss by healthista

How to fast for weight loss

Around 12 hours after the meal, when the meal has been completely processed and absorbed and assuming no further food has been eaten, the body has a chance to rebalance when it will then need to rely on its fat stores for energy to keep the body natural processes working efficiently. It is only at this stage that the body will start to release fat for use as fuel.

With modern eating patterns relying on not only three meals a day but often with snacks in between, it is easy to see how this fasting state is rarely achieved.

This therefore also means that insulin levels are invariably high as a result of this regular eating pattern, increasing the burden on the pancreas, which is the organ that releases insulin, as well as putting increased pressure on the insulin receptors that are bombarded with insulin throughout the day.

These reasons, amongst others, have contributed to the rise in the development of Type 2 Diabetes in recent years.

Intermittent Fasting should be viewed as a long term lifestyle choice rather than a crash diet

Thus a simple shift in our eating patterns can result in not only a reduction in the number of calories consumed, which helps our ‘calories in vs calories out’ energy balance equation, but also provides the body with a chance to recuperate and rebalance without having to focus on the digestive process and therefore reduce the risk of developing Type 2 Diabetes.

Working fasting into your life

Intermittent Fasting should be viewed as a long term lifestyle choice rather than a crash diet. Otherwise, it is likely that you will regain any weight lost if you resume your original eating habits.

It is also essential that you make healthy food choices; ensuring good nutrition is vital when fasting to ensure the body’s processes are taking place efficiently and effectively. Thus, planning your meals to make sure you are getting adequate nutrients is very important.

READ MORE: 12 weight loss tips this nutritionist has heard that ACTUALLY work

nutritious food, why fasting works for weight loss by healthista

There are 2 ways to successfully achieve this pattern of eating:

#1 The daily approach

The simple concept is to aim to fast every day for 16 to 18 hours a day and only consume your food in the remaining 6 to 8 hours.

For example, if you eat your evening meal at 6:00pm, then you would not eat your next meal until at least 12:00pm the following day, allowing an 18 hour fast in between.

#2 The weekly approach

This suggests that you eat normally five days a week and fast for two days, preferably consecutive days a week, reducing your calorie intake for those two days to a ¼ of their normal level (500 calories for women, 600 for men).

As long as you avoid bingeing for five days and starving for the other two, evidence suggests this can be effective as part of a longer-term weight management strategy.

READ MORE: Calorie Deficit – how to gradually reduce calories for weight loss

eating fruit, why fasting works for weight loss by healthista

Putting it into practice

To start with, increase the gap between dinner and breakfast. If you’re not hungry you could skip breakfast altogether; going from dinner to lunch works best.

Consider the ideal ratio of 16:8 hours, this means you’d be eating a lower-calorie but nutrient dense diet within the eight-hour window. Typically, this would be from midday until eight o’clock at night. Spread this over two meals and then fast until lunch the following day.

Factoring in a daily brisk walk will help to speed up your metabolism and maintain muscle mass

Repeat this routine at least two to three times per week. If you feel hungry any time outside of the eight-hour window, distract yourself with an activity or task so that you’re not so aware of the hunger pangs. Factoring in a daily brisk walk will help to speed up your metabolism and maintain muscle mass.

If you’re opting for the weekly approach, do not fast for longer than three days in a row to avoid a significant reduction in your metabolism and to protect against muscle loss. If you’ve embarked on this approach on a long-term basis, including a cheat day every now and again is not a problem!

READ MORE: Walking as therapy – 5 reasons Britain’s favourite nature presenter loves it

brisk walk, why fasting works for weight loss by healthista

5 ways to fast smart

There are a number of ways to make sure your meal provides the balance of nutrients whilst ensuring you are satiated.

  • Try a protein shake as a healthy option as a convenient meal alternative.
  • Include at least two to three portions of vegetables with each meal and two to three portions of fruit per day.
  • Include protein with every meal – this means meat, chicken, fish, eggs, cheese, pulses – will help you stay full and avoid cravings.
  • Include more healthy fats in your diet – foods such as olive oil, butter, avocado, nuts and seeds are a great place to start.
  • Reduce your intake of carbohydrates such as bread, pasta, potatoes and rice as well as those naughty sugary foods that we love like cakes, biscuits, sweets, chocolates and desserts.
  • In an ideal world, you should completely avoid alcohol but making a significant reduction of your intake is also great.

On the topic of drinks, make sure you have plenty of fluids that don’t contain (or have very few) calories including water and herbal teas during your fasting periods.

Steer clear of fizzy drinks and fruit juices and instead opt for energising Matcha tea or refreshing green tea with mint instead. Coffee and a builders brew shouldn’t necessarily be avoided but they should definitely be drank in moderation.

READ MORE: 8 best-tasting green teas for people who don’t actually like green tea

green tea, why fasting works for weight loss by healthista

Who shouldn’t fast?

  • People who are underweight; restricting calories may result in further weight loss
  • Children – their nutrient and energy requirements are different to adults and fasting may not allow a child to thrive
  • Pregnant or breast feeding mothers – pregnancy is a time to ensure good nutrients and adequate calories for a growing baby.
  • If you have an eating disorder, this is not for you. Even if you have struggled with an eating disorder in the past, you may find adopting an eating pattern that restricts food may trigger a relapse.
  • If you’re recovering from surgery. Restricting nutrient intake and energy production may impair repair after surgery
  • If you are feeling unwell or have a fever; it is important to listen to your body and avoid fasting if your body is not in optimal health
  • If you are taking any prescribed medications, Type 1 diabetics and diabetics on insulin; it is essential to consult with your GP before embarking on any weight loss programme

may-simpkin-headshot-6-lunch-mistakes-that-are-making-you-fat-by-healthista-comMay Simpkin is a UK registered practitioner with a Masters Science degree in Personalised Nutrition. She is an experienced clinician, practicing functional medicine from an evidence base, providing the latest research into nutrition.

She is bound by the code of ethics in clinical practice and has met the strict criteria required for BANT, the British Association for Applied Nutrition and Nutritional Therapy and the CNHCComplementary and Natural Healthcare Council, which is the council recommended by the UK Department of Health for complementary and natural healthcare services.

For more information on how to lose weight, nutrient-rich recipes, and ideas visit or Follow May on Instagram: @maysimpkinnutrition or Twitter @MaySimpkin or Facebook 

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