By Dr. Mercola
Could fasting for two days a week prevent age-related brain shrinkage, heart disease, diabetes, and possibly even cancer? New research suggests that fasting triggers a variety of health-promoting hormonal and metabolic changes. Fasting - quantified as consuming somewhere between 500 and 800 calories in a day - has been shown to reduce:
- Growth factor - a hormone linked with cancer and diabetes
- "Bad" LDL cholesterol
- Inflammation levels
Overall, it also helps lessen damage from free radicals (dangerous molecules that cause damage in your body). Furthermore, according to the featured article in the Daily Maili:
"Suddenly dropping your food intake dramatically... triggers protective processes in the brain... similar to the beneficial effect you get from exercise.This could help protect the brain against degenerative diseases such as Alzheimer's and Parkinson's."
Intermittent Fasting: A Good Alternative to Constant Calorie Restriction
While it's long been known that restricting calories in certain animals can increase their lifespan by as much as 50 percent, more recent research suggests that sudden and intermittent calorie restriction appears to provide the same health benefits as constant calorie restriction.
This is good news, as it may be easier to do for some people who cannot commit to chronically restrictive diet. The Daily Mail reports:
"Professor Mattson is one of the pioneers of research into fasting - a few years ago he made a breakthrough when he found rats could get nearly all the benefits of calorie restriction if the scientists only cut back their calories every other day.
On the next day the rats could eat as much as they liked and yet they showed the same benefits as rats on a low-calorie regimen all the time. Suddenly it looked as if humans could benefit from a form of calorie restriction regimen that, unlike daily restriction, is feasible to follow.
Now results of other trials are revealing the benefits.
In one study, reported last year in the International Journal of Obesity, a group of obese and overweight women was put on a diet of 1,500 calories a day while another group was put on a very low 500-calorie diet for two days, then 2,000 calories a day for the rest of the week. Both groups were eating a healthy Mediterranean-style diet. '
We found that both lost about the same amount of weight and both saw a similar drop in biomarkers that increase your risk of cancer,' says Dr Michelle Harvie, a dietitian at Manchester University who led the research.
'The aim was to find which was the most effective and we found that the women in the fasting group actually had a bigger improvement in sensitivity to insulin.' Improved insulin sensitivity means better control of blood sugar levels."
While I don't generally promote calorie restriction, it is an important piece of the puzzle, and this type of intermittent fasting may be helpful for many - especially in light of the compelling research supporting calorie restriction. Remember, fasting does not mean abstaining from ALL food, but rather a dramatic reduction of calorie intake.
You need to cut your daily calories at least in half, but can go as low as 500-800 calories a day. The KEY to successful calorie restriction, however, lies in which calories you cut, which I will review in a moment. But first, let's take a look at some of the health benefits of intermittent fasting.
The Surprising Health Benefits of Calorie Restriction
Interestingly, some of the mechanisms largely responsible for weight loss and diabetic control when fasting are also the ones responsible for the benefits to your brain. Research suggests that calorie restriction can protect brain cells and make them more resilient against stress. This protective effect is in part due to fasting's effect on leptin and ghrelin; two hormones involved in appetite regulation. According to Professor Mattson, these hormones are also involved in the process of renewing brain cells - especially in the hippocampus - when you are not overweight.
Your hippocampus is the area of your brain where most of your memory functions are located, and there's a strong relationship between the size of your hippocampus and memory performance.
According to the featured articleii:
"If you start putting on weight, levels of ghrelin drop and brain cell replacement slows. 'The effect is particularly damaging in your 40s and 50s, for reasons that aren't clear yet,' he [Professor Mattson] says. 'Obesity at that age is a marker for cognitive problems later.' The good news is that this brain-cell damage can be reversed by the two-day fasting regime, although so far Professor Mattson has shown this only in rats. A human trial is starting soon. There is reason to think it should work.
Fasting every other day had a striking effect on people with asthma in a small study he ran a few years ago. 'After eight weeks they had lost eight percent of their body weight, but they also benefited from the ability of calorie restriction to reduce inflammation. Tests showed that levels of inflammation markers had dropped by 90 per cent. As levels came down, their breathing became much easier,' says Professor Mattson."
There is one important caveat, however. Mattson's research showed that symptoms returned about two weeks after quitting the intermittent fasting, so it's really a lifestyle commitment, not a temporary fix. Some can handle intermittent fasting long-term whereas others might find it too challenging. Still, it's an option to consider if you're having health issues or weight problems.
Fasting and Exercise: Are They Compatible?
I've previously interviewed fitness expert Ori Hofmekler on the issue of fasting and exercise. According to Ori, fasting also has the surprising benefit of helping you reconstruct your muscles when combined with exercise. This is due to an ingenious preservation mechanism that protects your active muscle from wasting itself. In a nutshell, if you don't have sufficient fuel in your system when you exercise, your body will break down other tissues but not the active muscle, i.e. the muscle being exercised.
That said, neither Ori nor I advocate starvation combined with rigorous exercise. It's important to be sensible. And you need to consume sufficient amounts of protein in order to prevent muscle wasting. Also, while there's more science in support of calorie restriction than any other diet in the world today, there are side effects to chronic calorie restriction, such as decreased thyroid function and decreased testosterone.
In my own personal experimentation, I have definitely fasted too long and lost loads of muscle mass. So now I tend to use fasting if I have consumed foods that caused me to gain a few extra pounds. I will skip my breakfast and exercise fasting. My next meal will be lunch, and then I'll have dinner. This has worked quite well and allows me to easily drop a few pounds and get my body fat into the ideal range. It has worked so well that I am in the process of considering doing this on a permanent basis as it just makes loads of sense to replicate ancestral eating patterns that clearly did not have access to food 24/7,
Cut the Correct Calories...
One important fact that many tend to gloss over or ignore entirely when it comes to calorie restriction is which type of calories to restrict. From a biological standpoint, the important part is not really how many calories you eat per day; it's about getting the right nutrients. It's important to realize that all calories are NOT created equal, and will not have identical effects your weight or health. Their value depends on the types of food (nutrients) they're attached to.
In the US, six of the top 10 sources of calories are carbohydrates from sugars and grainsiii, and this is a major reason why so many Americans are overweight. They're simply eating far too many sugars. It's very important to restrict carbs when doing a calorie restrictive diet. Your body does not require sugars for optimal health, but it does require protein and fats.
When you cut out the sugars and carbs it is wise to replace them with high quality non-processed fats. Some of my favorites include organic grass-fed raw butter, eggs, coconut oil, avocados, and almonds.
There's very compelling evidence showing that calories from fat are far more beneficial for your health than calories from carbohydrates. And fear not... It's already been well established that stearic acid (found in cocoa and animal fat) has no effect on distorting your healthy cholesterol ratios at all, and actually gets converted in your liver into the monounsaturated fat called oleic acid. The other two, palmitic and lauric acid, do raise total cholesterol. However, since they raise "good" cholesterol as much or more than "bad" cholesterol, you're still actually lowering your risk of heart disease. And there are additional benefits.
Lauric acid (as from coconut oil) has shown to boost thyroid hormone activity along with the body's metabolic rate. This is obviously a huge advantage to those interested in weight loss or those who suffer from underactive thyroid.
I couldn't encourage you more to implement this program. It has radically improved my personal confidence in using diet choices to achieve high level wellness and optimal body fat. Cutting down on your grains and sugars, replacing them with high quality fats and skipping some meals, especially before exercise, seem to be a powerful combination to help you Take Control of Your Health.