Does intermittent fasting really work?

Combining an intermittent fast over nighttime with a high-quality plant-based diet and exercise will go a long way toward "adding hours to your days, days to your years, and years to your lives."

By ALAN FREISHTAT DECEMBER 19, 2024 01:52

Food organized in a refrigerator. (photo credit: RAWPIXEL)

In the world of weight loss and health, the next fad is always just around the corner. If you’ve been around long enough, you’ve seen hundreds of strange diets, like eating only grapefruits several times a day or eating only cabbage soup in order to lose weight. Yes, you lost weight on those diets, but then the weight probably came back with some extra pounds.

Maybe you remember the use of amphetamines to lose weight. One lady told me how her doctor prescribed them to her and how she did lose weight – and also got three hours of house work done in about an hour. But that weight didn’t stay off either. When the popular drug phen-fen was pulled off the market, people were very disappointed. It was highly effective. The problem is, it could kill you.

But what if when we hear about an intervention that isn’t solely reliant on what you eat, isn’t a medication or supplement, and people say you can even get a good result? I know of someone who lost a lot of weight without any radical changes to his diet; he simply stopped eating every evening at about 6:30 and resumed his eating about 8:30 the following morning. This person engaged in a type of intermittent fasting. What is this type of fasting, and does it really have a lasting, positive effect?

Professionally, we call this Time Restricted Eating or TRE. It comes in many different versions, that range from eight hours of eating solid food and 16 hours of only water, tea and black coffee, to five days a week of regular eating and two days where you eat 6 hours and fast 18. There are many other variations in between. Does it work – and if so, why?

THERE IS no shortage of studies, many of them positive, about the effects of eating less hours in the day. Some of these studies show improved weight loss and reduced type 2 diabetes, better brain health and reduced inflammation and oxidative stress: all positive. But a new study that came out this past September tells a different story.

Fruits and vegetables (credit: INGIMAGE)

“A study of over 20,000 adults found that those who followed an 8-hour time-restricted eating schedule, a type of intermittent fasting, had a 91% higher risk of death from cardiovascular disease.

“People with heart disease or cancer also had an increased risk of cardiovascular death.

“Compared with a standard schedule of eating across 12-16 hours per day, limiting food intake to less than 8 hours per day was not associated with living longer.”

That certainly turns much of the previous research on its head! A study published in The Lancet this past September showed that people doing TRE for three months had very little health benefit or weight loss. It must be pointed out that a lot of the early research was done on animals and not on humans. Perhaps now that we have more human studies, we will get a more accurate picture.

Diet quality is key 

One of the single most important variables has to do with diet quality. Does a person who fasts on a poor-quality diet, or a diet containing more fat, do as well as a faster who is eating a whole foods and plant predominant diet? Most experts agree that diet quality is still more important than when one eats.

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But what if I combine a high-quality diet and some version of time-restricted eating? That is what we do at The Wellness Clinic. First, we adjust the diet to be majority plant based. We make sure you are getting enough water and that you are getting adequate sleep. We also encourage exercise. But one of the things we also try to do is to be sure there is a 12-hour time period, in coordination with your sleep, where you don’t eat solid food. There is good science behind the 12 hours. Yes, there will be the rare occasions like the Passover Seder or a late wedding where you just will have to eat late. But as long as we follow the fasting schedule most of the time, it is effective. Why does this work?

THERE ARE two main things that tend to happen. First, you just end up eating less calories. All of the extra calories you may have consumed noshing in the evening are gone. But that is not the main effect. That 12-hour fast is great for your gut microbiome. It is one of our tools to encourage more anti-inflammatory microbiota and less inflammation, which is the outcome we are all looking for. So if you combine our gut-positive diet with this gut-favorable abstinence from eating for 12 hours, you will have a great combination that will help you lose weight, and by achieving positive gut-health, will help your general health and well-being. Another important side-benefit? A better night’s sleep.

It’s never just one thing that will give you positive health outcomes. But when we combine what science tells us from different disciplines, we can have amazing results and wonderful outcomes. It’s not just how many steps you take per day, how many fruits and vegetables you eat daily, or when you stop eating – it’s all important.

Yes, there are some contradictory studies and evidence about time-restricted eating. But it seems that not eating solid food most nights for 12 hours does have value. Combine that with a high-quality plant-based diet, exercise and all of the other wonderful aspects of lifestyle medicine, and this will go a long way toward “adding hours to your days, days to your years, and years to your lives.”

The writer is a wellness coach and personal trainer with more than 25 years of professional experience, a member of the International Council of the True Health Initiative, on the board of Kosher Plant Based, and is the director of The Wellness Clinic. alan@alanfitness.com