It’s important to make sure your health practices are based on facts and not fads – especially when it comes to weight loss! Diet fads and trends are a multi-billion dollar business and you want to make sure you’re not falling for a marketing campaign when it comes to your health. Since there are many myths, misconceptions, and beliefs when it comes to fasting, we decided to break them down here with the input from Olga Afonsky, LN, research-proven facts, and know-how to help you make informed decisions about fasting. [1]

Here, we’ll address some common facts and misconceptions about fasting 

You’re going to feel hungry all the time.

This is a myth. Will you feel hungry at times while fasting? Yes! But, it won’t last forever and feeling a few hunger pangs or grumblings here and there won’t kill you.  “When I bring fasting up with my clients, they say things like, ‘Fasting sounds terrible. I don’t like being hungry,’” says Afonsky.  “I explain that it’s just a matter of experiencing hunger, having the visceral knowledge about how that feels and that the hunger comes and goes. I also thought that once hunger comes, it just stays and gets stronger and stronger until you eat something. But that’s not true. Hunger comes, and then in 10 or 15 minutes, it’s gone. And then you are [usually] free from hunger and for another hour or two until it comes back.”  Studies on alternate-day fasting have shown that satiety – the feeling of not being hungry – improves by the second week, and hunger continues to stay low thereafter. [2] Other research finds that following a fasting-style diet can improve your appetite. [3]

Doing a prolonged fast may lead to more significant hunger, but that’s something you shouldn’t do until you have practiced with other types of fasting and discussed it with your doctor.

You have to do it perfectly to have results.

“I always tell my clients, ‘Pick [two days] when you think fasting would work in your week if you’re following a 5:2 type of plan,” says Afonsky. “But if for some reason, fasting is not going your way that day, then try it the next day or to the day after. You can always break the fast and eat, and try again when it is a good day. The flexibility is helpful.” If you’re following a 16-hour time-restricted eating plan and really need to eat before it’s time, tell yourself that day will be a 12-hour time-restricted fast and you’ll try again for the longer fast tomorrow. Research finds that one of the behavioral skills required for long-term weight loss is to anticipate challenges and prepare contingency plans. [4]

You can improve your immune system by fasting.

The good news is that there is some evidence that this may in fact be true. Intermittent fasting has been shown to restore gut microbiome homeostasis in mice, and fasting may improve good gut bacteria in humans, as well as help the body get rid of the old, worn-out intracellular components as part of the autophagy process. [5], [6] Having a healthy gut. [7] However, it should be noted that dietary restriction may put you at risk of nutritional deficiencies that are vital for healthy immune function – significant changes to your diet or prolonged fasting should always be discussed with your healthcare provider.   

Fasting appears to impact cells’ metabolic pathways and may also affect immune function – it has even been shown to decrease inflammatory markers in certain populations. [8] Following a diet with a fasting component has shown an improvement in symptoms in people who suffer from rheumatoid arthritis. [9]

You’ll live longer if you follow a fasting diet.

This conception is probably true, but more research is needed. Fasting and nutrition-based solutions have a number of potential health benefits and one of the most frequently discussed one is whether eating this way will add years to your life. Overall, fasting has been shown to decrease the incidence of diseases that could lead to an early death, including obesity and cancer, and possibly helping with heart health. [10], [11].

While animal studies show promising results where rodents live longer, healthier lives eating this way, we don’t have gold-standard studies that prove these results for humans. [12] “Unfortunately, you can’t put a group of humans on 30-percent calorie restriction for a few days for the duration of their life to see if they live longer,” says Afonsky. The observational studies do have pretty good results but there are no randomized controlled trials in humans, she says.  “People have used fasting for medicinal purposes for thousands of years and other studies show that calorie restriction can help with chronic diseases.”

It’s really hard to stick to.

This is a fasting myth! One of the easiest ways to start intermittent fasting (IF) or time-restricted eating (TRE) is to do it overnight. You’ll be working on your weight loss and health goals while you sleep. There are no special foods to eat, no prep work, and it pretty much doesn’t cost anything to follow a fasting diet. “In some ways, it’s easy because you just don’t eat,” says Afonsky. “Many of my clients find fasting a lot easier than they initially thought because there are many different ways to do fasting. My overall approach is super flexible, experiential and creative and a ‘let’s try to see what works’ mindset.”

Afonsky says many of her clients extend their overnight fast and skip breakfast to do time-restricted eating for 16 or 12 hours. “That seems to be the easiest one for most people to start their experimentation with intermittent fasting.” The other IF plan her clients like to try is the 5:2 plans. Two days a week they reduce their calorie intake to about 25 percent of what they typically eat a day and eat two meals. “People find IF, TRE and 5:2 doable and they often drink plenty of liquids to help them through the fasting days,” says Afonsky.

You’ll lose weight quickly.

The truth in this statement depends on the fast you’re following and how you were eating before you started a fasting plan. If you’re doing alternate-day fasting, you’ll probably notice weight loss the morning after your fasting day.

If you’re following a plan like the 5:2, Afonsky says she’s seen clients consistently drop a pound to two pounds after a fasting day. She had one client who cut out breakfast as part of this intermittent fasting plan and lost about eight pounds in one week, and four the next! “You could lose weight fast, and fasting could be very effective weight loss for some people. But I also have clients who don’t experience that rapid weight loss. It is still very individual in terms of the amount of weight that you’re going to lose.” One small 2019 study of humansfound that those who followed early time-restricted eating found that this method decreased the hunger hormone ghrelin and decreased the desire to eat. Eating this way may also help with fat oxidation and metabolic processes. [13]

It can help with cancer treatments.

This is a belief that might be true and an area where we’re seeing more research. “There are benefits of following a prolonged fast for those undergoing cancer treatments,” says Afonsky. Animal studies demonstrate that short-term fasting may help decrease the toxicity of chemotherapy while also increasing its efficacy, and studies in humans show promise, though more studies are needed. [14], [15]  Another study found that nightly fasting might help reduce the recurrence of breast cancer in women with early stage breast cancer. The study authors suggest that might be due to improvements in glucoregulation and sleep. “In cancer cells, their mitochondria are broken and they cannot use that for energy production,” says Afonsky. “They heavily depend on glucose. When you’re fasting and you don’t have a ton of glucose circulating in your bloodstream, the cancer is starving. You are starving the cancer cells by reducing glucose.” More research is still needed to make conclusions about the role fasting plays in cancer treatment and recovery but the science is looking promising!