Water Fasting

Dr Hana Kahleova How to tackle intermittent fasting

"When we pull together all the randomised clinical trials there is a linear relationship between the eating window duration and changes in body weight. The sweet spot seems to be at six hours."

Endocrinologist and researcher, Dr Hana Kaleova, has spent many years examining the value of intermittent fasting. Now, and with a massive number of research hours behind her, she has become one of the world's foremost exponents of short term fasting for health. She says the easiest way to do intermittent fasting is to start with a periodic fast.

“You just take a certain day, you can do one day a month or you can decide to do five days in a row or more days in a row,” she says. “You can do it as a onetime thing or you can do it one day a month periodically. That would be a less frequent form of intermittent fasting.”

The fast can be a water only, or you can also include vegetable and fruit juices. You can also do a modified fast where you eat raw fruit and vegetables with a super small caloric intake, about 500 calories a day, she says.

But, does it have any impact on fatty liver disease if you have it?

“One study of almost 700 people looked at the effects of fasting for an average of 8.5 days on liver fat. The study found that after only 8.5 days the liver fat content dropped by 30 per cent which was pretty effective.

“As you would expect the reduction in liver fat correlated with the number of fasting days. In other words the longer the fast, the bigger the change in liver fat and also with the change in BMI. The more weight you lose the more liver fat you lose.”

But, she says, “if eight days seems like a long time for you to fast, I’m completely with you. I recently finished a three day water fast and it felt long.

“You know, the food we eat is such an integral part of our life. We don’t even realise until we go through the withdrawal symptoms and we’re like, oh I feel like eating something, but oh

I’m fasting, ok, never mind, let me do something else. Amazing results possible

“But I also have some good news for you. You don’t have to do eight days. Even a smaller amount will give you some amazing results. It can make a huge difference not only for your liver but also for your immune system.

“If you want to fast more frequently, you can. Let’s say you do one day a week. A maximalist approach would be alternate day fasting where you fast every other day, which would be In her address to the recent International PlantBased Healthcare Conference held in California in September, Dr Hana Kaleova presented the latest research on the effects of fasting. Dr Kaleova is director of clinical research with the Physicians Committee for Responsible Medicine, and coauthor of 19 articles in peer-reviewed research journals. This article covers part of her address. To purchase access to all videos and slides from this conference go to: pbnhc.com

challenging for many people though.

“You would eat normally on the non-fasting days and you would not eat at all or you would do a modified fast and eat only a third of what you eat on the fasting days. It’s fairly challenging because you are changing your habits constantly and studies with alternate day fasting have a large drop-out rate.” Alternate day fasting

However, it works for some people, she said. One study looked at liver and alternate day fasting. Forty three people were randomly assigned to follow alternate day fasting or they stayed on their usual diet for eight weeks.

“The alternate day fasting reduced the elasticity of the liver by 15 per cent and liver fat by 20 per cent so it was fairly effective. But again, it’s fairly challenging to stick with this regimen in the long term. That’s why many people seek simpler options. One of them is time restricted eating or time restricted fasting.

“We know that our body has completely different needs based on our activity. If we are physically active our bodies needs are much different than when we sleep. When we are physically active we want to maximise the caloric intake and when we sleep we scale down the caloric intake right?

“Periodic time restricted eating basically limits the caloric intake into an eating window of a few hours. So, now the question is;

what’s the ideal length of the eating window?

“To illustrate what I mean by the length of the eating window let’s say you eat breakfast as six, lunch at noon and dinner at 6pm that would be a 12 hour eating window. If you want to reduce your eating window you could eat dinner at five which would be an 11 hour window, if you were to eat breakfast and hour later you would reduce your eating window to 10 hours.

“When we pull together all the randomised clinical trials there is a linear relationship between the eating window duration and changes in body weight. The sweet spot seems to be at six hours. Six hours is the ideal spot where you lose the most amount of weight and that would be most beneficial for fatty liver as well. Reducing it to four hours does not further reduce the body weight but prolonging the eating window will have less pronounced benefits for body weight. That would mean say breakfast at seven and lunch at 1pm. Are there any studies that have looked at such a model?

Fasting impact on pre-diabete

“One study looked at cardio-metabolic health in people with pre-diabetes who were randomised to either follow a 12 hour eating window, which is easy, or a six hour eating window shifted early in the day. People were done with lunch by 3pm. They were done with eating for the day by 3pm.

“It was a crossover trial so after five weeks the participants switched over to the opposite diet.

“This study found that the early time restricted eating has metabolic benefits that are independent of weight loss. Early time restricted eating increased insulin sensitivity, improved beta health functions, reduced blood pressure, reduced oxidative stress and also reduced appetite in the evening, which is huge.”

One group of people who are recommended to eat many small meals during the day and eat all day are those with type two diabetes. What would happen if their eating window were restricted to six hours?

“We conducted a randomised clinical trial which was published in Diet Pathalogia. The results are presented on six meals a day and on two meals a day. Both diets had the same caloric intake and the same macro-nutrient composition – they just differed in the timing.

Two meals a day, or six?

“People lost more weight on two meals a day, liver fat was reduced more on two meals a day, insulin sensitivity went up more on two meals a day, HbA1c as a marker of glycaemic control improved about the same on both, fasting plasma glucose was reduced more on two meals a day, and so was fasting insulin which is a good finding.

“We know that people with diabetes have a higher fasting hyperinsulinemia and then they lack the early postprandial secretion of insulin so reducing the fasting hyperinsulinemia is a really good finding.

“What was fascinating is that on two meals a day the depressive symptoms were reduced more and guess what, hanger was reduced more on two meals a day which is like unbelievable for most people. In fact, most of our study participants when they were about to join the study were like. ‘I don’t know if I can do this! Like, two meals a day! That sounds like I will be starving.’

“But nobody dropped out because they weren’t able to do it. In fact it took only a few days to adapt to this new system and at the end of the study people loved the two meals a day. They lost more weight, their diabetes got better and they just felt better and less hungry.

“Also its so convenient. You only prepare two meals a day instead of worrying about what you are going to eat six times a day. It makes your life so much easier. Aligning you meals with your circadian rhythms really pays off in terms of your metabolism and it’s good for your fatty liver as well.”

The case for a breakfast feast

Hana Kahleova is a firm believer in having a big breakfast every day. She says it helps you burn more calories during the day and points to a randomized clinical trial in 23 obese people which compared eating breakfast every day to fasting until noon for six weeks.

Eating breakfast daily resulted in a 76 percent greater physical activity thermogenesis during the morning compared with fasting during that period, despite no difference in energy intake.

Morning fasting resulted in partial dietary compensation (i.e., greater energy intake) later in the day. Furthermore, insulin sensitivity (the way your body responds to ingested carbohydrates) increased with breakfast relative to fasting.

So, starting your day off with a nice quality breakfast is like jump-starting your day, she says.

Other doctors are also taking note.

The American Heart Association has endorsed the principle that the timing of meals may help reduce risk factors for heart disease, like high blood pressure and high cholesterol.

The group issued a scientific statement emphasizing that skipping breakfast — which many of us do regularly — is linked to a higher risk of obesity and impaired glucose metabolism or diabetes, even though there is no proof of a causal relationship.

Fasting signals to the body to start burning stores of fat for fuel, researchers say.

“It seems our bodies are built to feast and fast,” Dr Kahleova told The New York Times.

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