Could Intermittent Fasting Work For You?

How often do you eat? If you’re like most fitness enthusiasts, you probably go beyond the three traditional meals and have five or even six small meals every day. And for years, this has been the prevailing wisdom. The driving force behind this approach is the idea that doing so will boost your metabolism and ward off the dreaded “starvation mode,” which all athletes struggle against. Many people who practice this sort of grazing also do so with the hope that they will be able to balance their blood sugar and avoid the midday crash that afflicts us all. A new approach to eating, however, promises to achieve all of that, plus more, while requiring you to do the exact oppose: Fast.

What is it?

Specifically, as the name Intermittent Fasting (or IF) suggests, the dieting method asks that you regularly go without eating. But there are several different approaches to IF that adjust both the frequency and duration of the fasts. Generally, intermittent fasting can be divided into two main categories: periodic fasts and daily fasts.

Although there are programs out there that offer specific fasting schedules, periodic fasts tend to be open to interpretation. These are usually 24-hour fasts that occur either once per year or even as often as once every week. It is recommended, however, that you don’t fast any more than one day each week.

The daily fast, despite its more intimidating name, is generally less severe since the actual duration of the fast is reduced. By limiting, your “feeding window” or amount of time that you allow yourself to eat during the day, you can prolong the natural fast that we all experience while sleeping. For example, the most popular programs require you to devote 16 hours to fasting, giving yourself an 8 hour eating window. This means that if your first meal is at 9am, your last meal of the day would by at 5pm. During that time you’re allowed to eat whenever you’d like, as long as you don’t exceed your normal caloric needs.

Why Fast?

But what are the benefits of fasting? And, if forcing your body into a severe caloric deficit can actually slow down your metabolism and cause muscle loss, why do it?

As with all health and fitness regimes, the proponents of IF tout a wide range of benefits, which include the ability to prevent type 2 diabetes, heart disease and obesity, as well as contribute to a longer lifespan. Counter-intuitively, Intermittent Fasting is also said to be able to contribute to muscle growth and a lean appearance.

But do these claims stand up to the test of clinical studies? In most cases, yes. But with a few expected caveats that will be discussed later.

Intermittent fasting does in fact help to improve insulin sensitivity, meaning that the hormone has a bigger impact on your body and elicits more of a response. A strong insulin response is key in maintaining balanced blood sugar levels and ensuring that the needed nutrients get to your muscles quickly. This improved use of insulin is responsible for the decreased risk of types 2 diabetes associated with intermittent fasting.

Studies have also confirmed that intermittent fasting causes the human body to target fat for fuel more aggressively than otherwise, which reduces both cholesterol and body fat. Of course, the trimmed look that comes from burning all that body fat is the most famous effect of intermittent fasting but there are many more important unseen, internal benefits.

Fasting also stimulates autophagy, your body’s way of clearing out potentially dangerous waste products, some of which have been linked with Alzheimer’s, Parkinson’s and other severe neurological diseases.

It is true that previous studies have suggested that a calorie-restricted diet can increase lifespan but these findings have since been called into question by newer research.

Cautions and Things to Know

Sure, intermittent fasting sounds like the solution to all sort of health problems and could even be just the thing to give you a boost towards your fitness goals. But, IF isn’t for everyone. People who have specific caloric and nutritional needs, especially pregnant women, should not picking up fasting. As a matter of fact, everyone should discuss the idea with their doctor before getting starting.

There’s a particular concern for people with heart conditions, as well. The effect isn’t full understood but some studies have shown that long-term fasting can cause a hardening of the heart’s tissue.

One of the largest concerns with IF is that the extreme hunger pangs make you gorge when you finally get to eat. Supporters say that while this is a difficult aspect of fasting, it will ultimately help you gain control over these cravings so that they don’t control you.

If you do decide to fast, you should start out with a daily fast, using the 16/8 model for men and 14/10 for women. This will help you start out slowly and build the self-control necessary for a full 24 hour fast.

Have you tried intermittent fasting? Please share your experience in the comments.

Sources

http://www.scientificamerican.com/article.cfm?id=how-intermittent-fasting-might-help-you-live-longer-healthier-life&page=2

http://www.sciencedaily.com/releases/2013/04/130426115456.htm

http://jap.physiology.org/content/99/6/2128.full

The Glycemic Index: What You Should Know

Your body is full of delicate balancing acts. Different chemicals are constantly competing to counteract each other and keep things running smoothly, in a process clinically known as homeostasis. This ability to self-regulate allows our bodies to maintain a healthy temperature, blood pressure and water levels. Another important example of homeostasis that has been receiving a lot of attention lately is blood sugar, or blood glucose.

Many diet programs utilize the glycemic index, a measure of how food affects your blood sugar levels, to achieve certain health benefits. How is blood sugar naturally controlled? How does food affect our blood sugar? What benefits can you expect from monitoring the glycemic index of your diet?

How Blood Sugar Works

Sugar, in the form of glucose, is used throughout your body as fuel at the cellular level. Generally, a healthy level of glucose in your blood is between 90 and 110 mg/dl, which ensures your cells have all the fuel they need to get their job done without being damaged. These levels are maintained by two hormones, insulin and glucagon, both released by the pancreas.

Insulin is the weapon of choice when blood sugar levels are too high. Once it’s in the bloodstream, insulin makes the cells absorb more sugar and tells the liver to store some for later use. This pulls the sugar from the blood and stops any potential damage.

Glucagon is released when blood sugar levels are too low and basically undoes the effects of insulin. This hormone signals to the liver that it’s time to release stored glucose into the blood, raising sugar levels.

When you eat, the carbohydrates in your food are broken down into sugar, which causes a spike in your blood sugar levels. In response, your body begins the cycle of insulin and glucagon to try to regain balance. The varying effects of food on your blood sugar is called the glycemic index (GI). Foods with a high GI are absorbed rapidly, making your blood sugar shoot up quickly and then plummet when insulin is released. Low GI foods digest slower and do not have such a drastic effect on your blood sugar.

Can It Help You Lose Weight?

Various diets attempt to control your blood sugar levels by means of this glycemic index, focusing on foods with a low GI that will have little effect on your blood sugar.

Although this type of diet is beneficial for people with blood sugar issues, diabetes or other related conditions, it is frequently used for weight loss. By nature, this diet will limit your intake of high-carb foods since these typically have a high GI. Compared to other low or no carb diets, though, a glycemic index diet is generally easier to follow because you don’t have to count carbs. This accessibility and sustainability make a glycemic index diet attractive. But does it work?

Lab results are mixed. Some studies have shown no more weight loss from following a GI diet than from following any other program, while others demonstrate a much higher potential for weight loss. Part of the problem could be the wide variation in GI diets leading to an inconsistency in testing. Usually, however, the GI diets that do cause weight lose encourage high fiber and protein intake which contributes to lower portions.

If you do plan on following a GI diet, Dr. David Katz, writing for U.S. News, stresses the importance of using the GI only for its intended purpose: measuring the effects of carbohydrates on blood sugar. Katz points out that these diets pay no attention to other vital nutrients like protein, fats and fiber and paint an unbalanced view of nutrition.

For weight loss, the GI can be incredibly useful to help you decide which carbohydrates to eat, but should be used in conjunction with a balanced diet.

Performance Enhancing Potential

Because carbohydrates are the main fuel used during endurance training, it seems logical that a high GI drink during exercise would be useful. However, a 2009 study published in the Journal of Science and Medicine in Sport found no difference in performance from high or low GI drinks. The researchers did note, though, that a low GI meal before exercise lessened the effects of cortisol, which causes your body to store fat.

Have you followed a glycemic index diet? Please share your experience with us in the comments.

Sources

http://www.pc.maricopa.edu/Biology/pfinkenstadt/BIO201/201LessonBuilder/UnitOne/Homeostasis/index.html

http://www.mayoclinic.com/health/glycemic-index-diet/MY00770

http://health.usnews.com/health-news/blogs/eat-run/2012/10/18/use-and-abuse-of-the-glycemic-index

http://www.ncbi.nlm.nih.gov/pubmed/18789762