Fasting Diets and Weight Loss - Part 1

Patient Expert

While fasting has traditionally been used as a show of faith or as a method to convey political views or protest,   many people also use it as a method to promote weight loss and cleanse the body of toxins.

A fasting diet can be drinking water or eating only raw foods for a limited period of days or it can be the restriction of food on alternating days. Some of these diets restrict the dieter to drinking only water, juice or tea while others involve an extreme reduction of calories but do not do away with food completely. Whereas this might be considered an extreme approach to dieting by many, the question then become how well does fasting work when used as a tool for weight loss?

Health Concerns About Fasting

Standard weight loss methods requires burning more calories on a daily basis than the number of calories consumed on a daily basis. By simply not eating to lose weight, a person faces certain health risks.

Metabolic Rate

When a person is fasting, the body responds to being starved and lowers the metabolic rate. Eating less than 1200 calories on a daily basis produces the same effect as a method of energy conservation.

Lowered metabolism causes a person to store energy. Once the fast is done, a person will probably gain back the weight that has been lost and perhaps a few pounds more. Appetite hormones revive after fasting, and you might actually feel hungrier than usual and binge eat as a result.


Fasting causes an extreme decrease in leptin, the blood component that signals we have had enough to eat. This decrease makes it more difficult to lose weight and encourages overeating once the fast is completed regardless of body fat levels.

Thinner people might lose weight when fasting while obese people may not because of different chemical changes that take place between the opposite body types. Fasting increases anti-inflammatory mechanisms of the immune systems of lean people but does not do the same in obese people.

Fasting can alter mood and be a catalyst for depression.

Extended Fasting

Fasting for longer periods of time can be quite harmful. The vitamins, minerals, and other nutrients the body needs and which are gotten from food are denied. An insufficient amount of these important nutrients can lead to symptoms of fatigue, dizziness, constipation, dehydration, gallstones, and an intolerance to colds.

Even short-term fasting is not recommended for people who have diabetes because of the variance of increased and decreased blood pressure. Pregnant women or women breastfeeding should not fast nor should any person who has a chronic disease.

Conversation with a physician should be had before fasting or going on any diet to determine the most appropriate and safe fit.

Now that some of the concerns about fasting have been explored, I will share what some advocates of fasting believe in my next post, Fasting Diets and Weight Loss - Part 2.

References: -  - accessed 8/1/12
WebMD -  - accessed 8/1/12