7th July 2023

Intermittent fasting myths you need to stop believing!

Often when it comes to diet and nutrition, misunderstandings or misinformation can lead to myths. Today, we’re busting intermittent fasting myths and addressing misconceptions by giving you key information based on science.

What is intermittent fasting? 

Intermittent fasting is when you stop eating for a part of each day, or restrict your calorie intake for a few days each week. Research shows that intermittent fasting has the potential to reduce your risk of type 2 diabetes, help you live longer, improve cognitive function, improve sleep, and even improve resistance to stress.[1][2]

Being asleep for eight hours (ideally) a night already counts as a period of fasting but intermittent fasting expands this usual fasting window further into the day. Another form of intermittent fasting is alternating days of fasting with days of eating throughout the week. 

Here at The Fast 800, we encourage our members to try Time Restricted Eating (TRE), if it’s right for them, which enables you to extend your usual night-time ‘fast’ by eating an early dinner or skipping breakfast to condense your eating period into an eight, ten, or twelve-hour window. Alternatively, The Fast 800 5:2 diet incorporates the method of intermittent fasting by restricting your calorie intake for two days a week to 800 calories, which counts as a fast. 

Despite these widely researched benefits, there are still plenty of intermittent fasting myths that need busting.

1. MYTH: Breakfast is the most important meal of the day

The first of our intermittent fasting myths, and possibly the most widespread! Interestingly, it’s widely thought that this idea originated as a marketing ploy from cereal brands, rather than being a science-backed truth.
Eating breakfast should depend on your schedule or preference: if you wake up hungry, then eating a healthy, Mediterranean-style breakfast can be beneficial, and will help keep your blood sugars steady.
On the other hand, skipping breakfast if you’re not hungry isn’t harmful and does not necessarily result in weight gain or an increased appetite later in the day. Furthermore, there is plenty of research that suggests extending your fasting window (breaking your fast later in the day) has plenty of health benefits including improving metabolic health and increased weight loss.[3]

2. MYTH: Fasting puts your body in ‘starvation mode’

This myth is the belief that withholding food causes your body to shut down your metabolism, and hold onto fat. However, the opposite is true in the short term: studies have revealed that some forms of fasting can actually boost the metabolism due to an increase in blood levels of norepinephrine as a result of a decrease in serum glucose which stimulates your metabolism and breaks down body fat cells.[4]

3. MYTH: Eating smaller, more frequent meals helps you lose weight

Some believe that ‘little and often’ is the best way to increase your metabolic rate and burn more calories, however, this will more likely lead to raised blood sugars throughout the day. There are many studies that demonstrate how increasing or decreasing meal frequency does not affect how many calories you burn.[5][6] Furthermore, in a study of 16 adults with obesity, no difference in weight, fat loss, or appetite occurred when doubling their meal frequency.[7]

At The Fast 800, we believe the key to weight loss, and intermittent fasting, is eating filling and nutritious food which will keep you satiated until your next meal. We have plenty of fasting-friendly, filling recipes on our Online Programme for this very reason.

4. MYTH: Intermittent fasting makes you lose muscle

There are several studies that suggest intermittent fasting is better for losing weight and preserving muscle than regular calorie-restrictive diets.[8] 

If muscle loss does occur when intermittent fasting, it’s more than likely a result of a lack of exercise or protein intake when eating, rather than as a result of restricted eating times. It’s important to keep up your protein intake when intermittent fasting to prevent muscle loss.

5. MYTH: You have to fast for at least 16 hours to see the benefit

The intermittent fasting myth that you must fast for 16 hours at a time to see benefits is just that: a myth. Time-restricted eating (TRE) allows extra time for cell repair pathways to engage between eating and this can happen effectively in as little as a 12:12 (12 hours of eating, 12 hours of fasting) ratio to see benefits.[9] The length of your eating window is down to personal preference and whether you can sustain this. However, eating filling, nutritious meals no matter how small your eating window is will ensure you feel fuller for longer.

There will always be misconceptions about what is healthy and what isn’t when it comes to diet, but at The Fast 800, we’re passionate about debunking myths (particularly intermittent fasting myths) and providing science-backed information. Sign up for a 7-day free trial of our Online Programme for a range of meal plans, with intermittent fasting options, to help you with your health goals, as well as access to guided exercise courses and exclusive expert advice.


Johnson JB, et al. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radic Biol Med. 2007 Mar 1;42(5):665-74. doi: 10.1016/j.freeradbiomed.2006.12.005. Epub 2006 Dec 14. Erratum in: Free Radic Biol Med. 2007 Nov 1;43(9):1348. Tellejohan, Richard. PMID: 17291990; PMCID: PMC1859864.

Sutton EF, et al. Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metab. 2018 Jun 5;27(6):1212-1221.e3. doi: 10.1016/j.cmet.2018.04.010. Epub 2018 May 10. PMID: 29754952; PMCID: PMC5990470.

Azevedo FR, Ikeoka D, Caramelli B. Effects of intermittent fasting on metabolism in men. Rev Assoc Med Bras (1992). 2013 Mar-Apr;59(2):167-73. doi: 10.1016/j.ramb.2012.09.003. PMID: 23582559.

Zauner C, Schneeweiss B, Kranz A, Madl C, Ratheiser K, Kramer L, Roth E, Schneider B, Lenz K. Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine. Am J Clin Nutr. 2000 Jun;71(6):1511-5. doi: 10.1093/ajcn/71.6.1511. PMID: 10837292.

Bellisle F, McDevitt R, Prentice AM. Meal frequency and energy balance. Br J Nutr. 1997 Apr;77 Suppl 1:S57-70. doi: 10.1079/bjn19970104. PMID: 9155494.

Leidy HJ, Armstrong CL, Tang M, Mattes RD, Campbell WW. The influence of higher protein intake and greater eating frequency on appetite control in overweight and obese men. Obesity (Silver Spring). 2010 Sep;18(9):1725-32. doi: 10.1038/oby.2010.45. Epub 2010 Mar 25. PMID: 20339363; PMCID: PMC4034047.

Cameron JD, Cyr MJ, Doucet E. Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. Br J Nutr. 2010 Apr;103(8):1098-101. doi: 10.1017/S0007114509992984. Epub 2009 Nov 30. PMID: 19943985.

Varady KA. Intermittent versus daily calorie restriction: which diet regimen is more effective for weight loss? Obes Rev. 2011 Jul;12(7):e593-601. doi: 10.1111/j.1467-789X.2011.00873.x. Epub 2011 Mar 17. PMID: 21410865.

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