Fasting Diet

Fasting diets introduction

Fasting to lose weight is nothing new, but a new crop of trendy diets has brought the practice back into the potlight.

Diets like the 5:2 Diet, Lemonade Diet, and others claim to help people lose weight fast and detoxify the body, but the research to support those claims is spotty at best.

What are intermittent fasting diets?

The 5:2 diet was recently the topic of a popular BBC documentary and book, and it's based on the principle of intermittent fasting (IF) or alternate-day fasting (ADF). Intermittent fasting means you eat normally at certain times and then fast or dramatically reduce your calorie intake at other times.

The 5:2 diet calls for eating normally on five days of the week and fasting (eating no more than 500 calories for women and 600 for men) on the remaining two days. Proponents of the 5:2 diet and similar fasting diets claim that they can increase lifespan improve how the brain works, and protect against disease; but most of those claims are based on research conducted in animals like rats and mice.

There are some small studies in humans that suggest that intermittent fasting diet may help promote weight loss and reduce risk factors for heart disease, diabetes, and other weight-related health problems. For example, a small 2012 study in Nutrition and Metabolism showed 30 obese women who followed a liquid intermittent fasting diet lost 8.8 pounds and 2.3 inches from their waistlines after eight weeks. (Excess body fat around the waist has been associated with a higher risk of heart disease.)

What are detox diets?

Other types of fasting diets that have been in the headlines recently are "detox diets." Celebrities often claim to use these diets to lose weight quickly for an upcoming film or red carpet appearance. For example, singer and actress Beyonce reportedly used the Master Cleanse (also known as the Lemonade Diet) to lose weight to prepare for her role in Dream girls.

The Master Cleanse, or Lemonade Diet, claims to help people lose weight, flush the colon, and rid the body of toxins and parasites. It's a liquid fasting diet that consists of drinking a concoction of lemon juice, maple syrup, cayenne pepper and water throughout the day and using laxatives for about two weeks. But experts say there is no solid evidence that these types of detox diets actually "cleanse" your insides.

"They say you are cleansing your system, but there is really no data to support that," said Angela Lemond, RDN, spokesperson for the Academy of Nutrition and Dietetics in Plano, Texas. "Our bodies have an amazing ability to cleanse itself," said Lemond. "If you want a good cleanse, make a goal of eating nine servings of fruit and vegetables a day, and you'll get your cleanse."

What are the downsides of fasting diets?

Lemond says while intermittent fasting and liquid fasting diets may promote short-term weight loss, the challenge is maintaining that weight loss over the long term. "At the end of the day, these are all low-calorie diets. They are going to yield weight loss," said Lemond. "A lot of people say they are 'cleansing,' but they are really just trying to lose weight."

"A lot of studies associate fasting with losing lean, metabolically active tissue and minimal loss of fat tissue," said Lemond. "That will give quick weight loss, but for most people, it is not a sustained weight loss." Lemond says it's the lean, fat-burning tissue in your body that helps you keep weight off. If you lose it due to fasting, "you're worse off than when you started."

?What are the health risks of fasting diets

Although more research is needed to fully understand the long-term benefits and risks of fasting diets, Lemond says there are also short-term risks to consider. "There is an immediate side effect of irritability and fatigue that can't be underestimated," said Lemond. In addition, Lemond says fasting for more than three days can impair immune system function and make you more vulnerable to infection and illness.

Anyone considering a fasting or detox diet should first consult with a health care professional, and certain people should never try one of these diets. For example, Lemond says fasting diets are not recommended for people with diabetes because such an extreme diet can interfere with blood sugar control. Also, fasting or any other type of diet that severely restricts calories is not recommended for pregnant or women who are breastfeeding. People with other medical problems and anyone who takes medicine need to be careful because many medications are recommended to be taken at certain times either with or without foods; checking with your doctor(s) that prescribe your medications before you begin any major diet change is strongly advised.

:REFERENCES

- Angela Lemond, RDN, CSP, LD, Spokesperson for the Academy of nutrition and Dietetics, Plano, Texas. - Mattison, J. Nature, Sept. 13, 2012.- Varady, K. American Journal of Clinical Nutrition, July 2007.

- Kroeger, C. Nutrition & Metabolism, 2012.

- People. "Red Carpet Cleanses." March 2, 2009.- Themastercleanse.org.

- Woolsey, T. The Complete Master Cleanse. Ulysses Press. 2007.

- PubMed Health, "Does the 5:2 intermittent fasting diet work?" Jan. 14, 2013.