Fad diets come and go, but fasting has been around for thousands of years. It’s been used for political protest, spiritual preparation, and as a treatment designed to rid the body of harmful substances, but have you ever considered using it as a strategy for losing weight?
What is the Definition of Fasting?
Fasting is the act of willingly foregoing food for a period of time. Before the advent of agriculture, our ancestors had no choice but to abstain from food when food was scarce. During times of feast, excess calories are stored to tide the body over during times of severe food shortage.
Tell Me a Reason Why I Should Fast
Fasting gives your body a much-needed break from the stress of digestion. Today, about half of all Americans are overweight. This implies that a great number of people are consuming too many calories every day. These are mostly calories without nutrients. Overconsumption of empty calories stresses the liver and kidneys, which are responsible for filtering out toxic substances, and creates an accumulation of food waiting to be processed. Toxins are stashed in fatty tissue, to be dealt with later. When you stop eating for a period of time, you give your body a chance to catch up, to heal and repair the damage.
The Physiology of Fasting: Ketosis
Your body needs energy in the form of glucose in order to survive. Glucose is produced by the break down of glycogen, which is made by and stored in the liver and muscles. During the first day of a fast, almost all glycogen reserves are used up. At that point, fat is used in a process called ketosis. For women, it begins on the second day of fasting. For men, it’s the third day. During ketosis, the body breaks down fat molecules for energy. Until the body enters ketosis you may feel hungry and energy depleted. Once ketosis is established, you will feel that your hunger pangs are minimized, mental alertness is restored and energy levels increase.
Am I Going to Starve?
The amount of time a person can fast varies depending on the needs and goals. You should never fast to the point were starvation kicks in. Starvation occurs when the body has to use vital tissues to sustain life, because all of the stored energy sources (carbs and fat) have been depleted.
Will I Suffer Muscle Loss?
Some muscle loss takes place mainly on the first day of a fast. When you stop eating, the body converts muscle tissue into glycogen. This process does not continue, though. The brain alone would require the conversion of a pound of muscle tissue per day in order to function. By shifting to ketosis, the body preserves muscle mass and taps into its fat reserves.
How Much Fat Will I Burn?
In the initial phase of a fast, it may seem like you’re losing weight quickly, but that’s because most of the weight you have lost is water. In fact, it’s important to drink plenty of water while fasting, to avoid dehydration. Once your body enters ketosis, you can expect to lose about 3-4 pounds of fat per week.
How Long Does a Fast Last?
Typically, a fast does not take more than just 1-3 days. Generally, it is not safe to fast for an extended period of time unless you receive medical guidance. It is not uncommon for advocates of non-conventional medicine to fast for half or even a whole month in an attempt to treat long-lasting ailments.
Is Fasting to Lose Weight Considered Healthy?
Experts’ opinions differ on this issue. Some say that fasting should not be attempted at all. Others point to the multiple health benefits they have witnessed as a result of fasting. Each side of the issue has credible arguments.
One expert in favor of fasting is Joel Fuhrman, M.D. He wrote a comprehensive book about the subject called Fasting And Eating For Health. He and other fasting enthusiasts list these upsides:
- Since the American diet is deficient in nutrients, the body cannot free itself from toxins on its own and needs assistance. When you eat empty calories, but also through normal metabolism, your cells accumulate oxidizing substances. This condition leads to premature aging, as well as vascular disease, diabetes, and vital organ deterioration. By fasting, you give your body the opportunity to purge waste products.
- Overweight and obese individuals have difficulty ‘just saying no’ to poor food choices. Fasting can change your relationship with food, and gradually enhance discipline.
- Some persistent conditions associated with obesity do not respond to conventional treatments. Fasting for just four days per month can have beneficial effects.
- Scientific research has proven that periodic fasting combined with a calorie-restricted diet lengthens longevity.
Those who oppose fasting for weight loss list these downsides:
- When you go without food, your resting energy expenditure slows down by as much as one fifth. When you begin eating again, the slower metabolism makes your body more vulnerable to weight gain.
- The ultimate goal of a weight loss program should be a healthier lifestyle that includes reduced calories and increased activity, not drastic measures such as going without food.
- Calcium and protein are two essential nutrients that your body cannot live without. If you’re not getting protein in your diet, your body resorts to muscle mass. If you’re not consuming calcium, your body will take it from your skeletal system, which may cause osteoporosis.
- Most people don’t drink enough fluids during a fast and wind up becoming dehydrated.
- Building up muscle mass is a desired outcome because muscle boosts your basic metabolism, which means that your body burns more calories while at rest. Fasting goes against this goal, since it leads to muscle mass loss, to significant degree sometimes.
So with equally persuasive arguments on both sides of the issue, should you make fasting part of your plan of action to lose weight? One thing to remember is that all of that extra fat on your body is storing toxic material that needs to be dealt with sooner or later. If you’ve noticed that you often seem to develop a collection of unpleasant symptoms while on a diet – such as a headache, rash, runny nose, and aches that feel like the flu – that could be your body catching up on its detoxification every chance it gets.
Fasting allows you to plan for that ‘healing crisis’ by designating a day to forego food, drink plenty of liquids, and get lots of rest. Once the fast is over, although your metabolism will be slower, your digestive tract will be cleaner and will use fuel much more efficiently.
How Do I Fast Safely to Lose Weight?
It is advised that you do not try fasting for longer than three days without a doctor’s supervision. For short fasts, it’s still a good idea to have someone monitor you. If you have serious health problems or if you’re taking medication, consult your doctor before embarking on a fast.
It is recommended that as you approach the day of fasting you progressively decrease the amount of food you consume. As a first step, stop eating all meat and dairy. The next day, eliminate beans, grains, and nuts. On the eve of the fast, eat only light foods – soup, salad, and fruit. Reverse this process after you finish fasting by incorporating heavier foods incrementally into your diet. And of course, drink lots of pure water during the fast, to avoid dehydration and flush out toxins.
If traditional fasting for weight loss has both pros and cons, then how can one decide whether fasting, as a means to shed pounds, is good or bad? Is there a way of fasting that eliminates the cons and multiplies the pros? Sure there is! It is called Intermittent Fasting—a clinically studied and well-research type of fasting, which I am going to talk about in my next guest post (coming tomorrow).
About Author: Biologist Matthew Papa, PhD, worked as a postdoctoral research fellow at Washington University in Saint Louis, MO, from 2004 to 2010. He enjoys blogging about obesity-treatments and best weight loss programs.
Image credit: Alan Cleaver