How Intermittent Fasting Can Help You Lose Weight

Weight loss continues to be a significant issue for many people. Not only does obesity affect looks, self-image, and self-esteem, but it is also linked with several metabolic and systemic diseases like hypertension, diabetes mellitus, and cancer.

While many people know about intermittent fasting as a method of weight loss, not many understand how exactly it can help them burn fat and achieve optimal weight loss. The result is that many such people either starve themselves into malnutrition in the name of intermittent fasting or end up binge eating at the end of the fasting period.

Interestingly, understanding how intermittent fasting can help you lose weight will help you maintain a healthy weight like never before. Intermittent fasting is effective for weight loss and other systemic conditions like hypertension, type 2 diabetes, cancer, as well as obesity, so after seeing this, you might not need too many of those mythical ideas like slimming teas any longer.

What is Intermittent Fasting?

Intermittent fasting is a method of dietary control that gives your body enough time to efficiently utilize consumed/stored calories before introducing more calories. It is a kind of dietary self-awareness or mindfulness.

Intermittent fasting (IF) is a dietary approach involving alternating between eating and fasting on a regular schedule. Unlike traditional dietary methods that focus on what to eat and what to avoid, intermittent fasting is all about when to eat.^[1]Intermittent Fasting: What is it, and how does it work? | Johns Hopkins Medicine

Intermittent fasting works by allowing the body to fully utilize ingested calories before taking on new ones. Thus, the body stores very minimal calories while most of the calories and nutrients are channeled into growth, metabolism, and development, bearing in mind that the most important cause of obesity or excessive weight gain is an imbalance in energy intake and expenditure.

Think about it as you deliberately allow your body to use up what you fed it before feeding it another. This is unlike situations when one eats around the clock without allowing the body to use up excess calories stored before eating again.

How Does Intermittent Fasting Work for Weight Loss?

The physiology behind intermittent fasting is summed up in one term: metabolic switching. After food digestion, your body converts the food into energy and essential nutrients for growth and development. It releases glucose into the bloodstream for immediate energy and stores the rest as glycogen and fats with the help of the hormone Insulin.

Hours after the meal, the body begins to fall back on the energy reserves after it has depleted the immediate glucose molecules circulating in the bloodstream. These energy reserves include glycogen and fats. Glycogen stores in the liver are first depleted before a second switch to body fats.

The human body prioritizes energy for all its metabolic processes and would do anything to get energy. This is why glycogen and fats are stored in the first place. However, people with low metabolic requirements (probably due to inactivity) who eat frequently do not allow the body sufficient time to exhaust the stores before adding more.

Glycogen stores are depleted after about 12-24 hours of fasting, depending on the person’s level of physical activity and the body’s peculiar metabolism.^[2]Glycogen: What It Is & Function – Cleveland Clinic After this, the body makes a second switch to fat metabolism for energy.

Benefits of Intermittent Fasting

Intermittent fasting has shown significant promise for weight loss and glycaemic control in type 2 diabetes and has been found to play a beneficial role in the management of cancer.^[3]Welton S, Minty R, O’Driscoll T, Willms H, Poirier D, Madden S, Kelly L. Intermittent fasting and weight loss: Systematic review. Can Fam Physician. 2020 Feb;66(2):117-125.

For type 2 diabetes, studies have shown that intermittent fasting not only lowers fasting glucose levels but also increases oral glucose insulin sensitivity, decreases C-peptide levels, and decreases glucagon levels, which are all positive predictors of good glycemic control in diabetics.^[4]Ibid. Welton et al., 2020. Can Fam Physician

For cancer, recent studies have shown that intermittent fasting reduces cancer risks due to lowered glucose levels, insulin, leptin, and higher adiponectin, which are all linked to cancer etiology. Intermittent fasting also improves quality of life, improves neutropenia and seizures in patients with brain cancer, reduces the recurrence rate of breast cancer, and is generally safe for cancer patients.^[5]Tiwari S, Sapkota N, Han Z. Effect of fasting on cancer: A narrative review of scientific evidence. Cancer Sci. 2022

In addition to the above, intermittent fasting may also help protect against heart disease by lowering cholesterol levels and age-related neurodegenerative diseases, Dr Mark Mattson, PhD, a John Hopkins neuroscientist, said from his research.^[6]Mark P. Mattson – The Solomon H Snyder Department of Neuroscience

Best Methods of Intermittent Fasting

To utilize intermittent fasting for weight loss and maintenance of health, you have to know the different types of intermittent fasting. Several methods of intermittent fasting have been described so far. These vary based on the duration of fasting relative to the other time available for eating.

Here, we see five intermittent fasting approaches you can choose from.

1. The 5:2 IF approach: The 5:2 method of IF involves fasting for 2 days in seven days by consuming only 500-600 calories on the fasting days. During the two days of intermittent fasting, you are allowed to eat as long as your calorie intake does not exceed 600 calories.
2. The 16/8: This method involves fasting for 16 hours a day and eating only within an 8-hour timeframe. It is also known as Leangain’s diet.
3. The 12-hour fast: The 12-hour intermittent fasting method involves consuming your desired calories within 12 hours and fasting for the remaining 12 hours every day. This method, together with Leangain’s diet, can be made so that the fasting period coincides with sleep time, making it easy for beginners to adopt.
4. OMAD intermittent fasting: OMAD stands for one meal a day. It is the type of intermittent fasting that involves consuming just one nutrient-dense, high-calorie, high-volume meal a day. The recommended approach is to eat the meal within one hour and consume nothing except zero-calorie hydration for the remaining 23 hours of the day. It is practically achieved by fasting either from breakfast to breakfast, lunch to lunch, or dinner to dinner.
5. Alternate-day IF: This involves alternating between days of regular eating and fasting/reduced calorie intake. One eats normally one day, and either does a total fast the next day or eats a low-calorie diet the next day, typically around 500 calories at maximum. The rule is restricting your calorie intake to only 30% of your regular intake on fasting days and feeding adequately on non-fasting days.

Limitations of Intermittent Fasting for Weight Loss

Weight loss from intermittent fasting varies from person to person, but most people typically lose 2-4 pounds in one week from OMAD intermittent fasting, a report says. While intermittent fasting has shown significant promise as a primary care intervention for obesity, it has the following limitations.

1. Studies have not demonstrated the long-term effects/consequences of intermittent fasting, its sustainability, or its health effects.
2. It may not be advisable for special groups of people, including pregnant and lactating women.
3. Not getting enough nutrients during the eating periods may result in unhealthy weight loss due to malnutrition.
4. It may affect one’s physical activity at work, particularly if one has many fasting hours during working hours.

How to Successfully Lose Weight Through Intermittent Fasting

Depending on your weight loss goals, choose an IF method that suits your goals. The alternate-day fasting and the 16/8 methods are considered the most effective IF methods for weight loss and sugar control, but people starting intermittent fasting for the first time may find the 12-hour fasting method the easiest to start with.^[7]6 ways to do intermittent fasting: The best methods – Medical News Today

Here are effective tips on how to successfully lose weight through intermittent fasting without developing untoward complications.

1. Start small but consistent

You don’t necessarily have to jump into one of the difficult intermittent fasting methods because you know people who are doing them. For example, instead of starting with alternate-day fasting or the 16/8 method, start with the 12-hour fasting or the 5:2 approach.

It is important to note that consistency is key. Intermittent fasting may be an unsustainable way to lose weight in the long term, which is why you need to carefully consider which method you can sustainably practice, considering your peculiar situations, occupation, and activities.

2. Healthy Eating

Intermittent fasting might help effectively mop up excess calories from junk food, but that doesn’t mean you should eat anyhow you like. Eating healthy is one way to effectively harness the power of intermittent fasting for weight loss.

During your eating window, eat healthy food rich in essential nutrients and fiber that will not only be available during the fasting period but also not produce toxic by-products afterward. For example, while too much soda during your eating window might not produce long-lasting energy for your body, they have also been shown to erode bones and cause tooth decay.^[8]Joshi, Kiran & Pande, Ashutosh & Joshi, Tanuj. (2020). A Review on Hazardous Chemicals Present in Junk Food. Shanghai Ligong Daxue Xuebao/Journal of the University of Shanghai for Science and … Continue reading^[9]Abonmai, Khiumajuliu & Rachna, & Dular, Sunil & Bhardwaj, Sameeksha. (2022). Junk food and its impact on Health. Bull. Env. Pharmacol. Life Sci

3. Stay hydrated

Staying hydrated is extremely important to reap all the weight-loss benefits of intermittent fasting. Water is a necessary requirement for proper metabolism in the body; thus, adequate hydration can help maintain proper fat hydrolysis and other metabolic reactions.

Drinking water regularly can also give a feeling of fullness during fasting, prevent dryness of the gastrointestinal tract, and prevent symptoms of gastritis or peptic ulceration. This can help you resist your urge to eat during your fasting hours.

Also, adequate hydration can help you maintain a healthy balance of body weight while your fats are being metabolized into energy. Water makes up a significant proportion of body weight. Inadequate hydration can thwart your IF goals or tilt one into severe medical conditions that were never anticipated.

4. Regular exercise

Intermittent fasting could also be combined with regular exercise for better weight loss results. Research showed that, combined with different modalities of exercise, intermittent fasting can better optimize body weight, blood pressure, and the body’s lipid profile while eliciting exercise training adaptations.^[10]Gabel Kelsey, et al. A Narrative Review of Intermittent Fasting With Exercise. Journal of the Academy of Nutrition and Dietetics, Volume 125, Issue 2, 153 – 171, compared with a control diet (dietary restriction but not fasting) plus exercise.^[11]Kazeminasab F, Baharlooie M, Karimi B, Mokhtari K, Rosenkranz SK, Santos HO. Effects of intermittent fasting combined with physical exercise on cardiometabolic outcomes: systematic review and … Continue reading

Depending on the intensity of the exercise, you might want to take a light carbohydrate food/drink or eat a well-balanced diet before an exercise. This will help provide you with enough energy throughout your exercise session. Again, continue to rehydrate during and after exercising.^[12]Is it better to eat before or after exercise? – HRI

It may be unadvisable to exercise during intermittent fasting when you have many hours to fast to prevent extreme fatigue and wasting. However, a helpful approach is to schedule your exercise sessions at the end of the fasting period and then replenish with an adequate calorie diet during your eating period. Exercising for the last 2-3 hours of the fasting period can enhance fat utilization and weight loss.^[13]Zouhal H, Saeidi A, Salhi A, Li H, Essop MF, Laher I, Rhibi F, Amani-Shalamzari S, Ben Abderrahman A. Exercise Training and Fasting: Current Insights. Open Access J Sports Med. 2020

5. Knowing your limits

As an extension to the point above about starting small, it is important to know when to quit fasting. Listening to your body’s limits will help you safely utilize intermittent fasting without compromising your health.

Intermittent fasting, or fasting for weight loss, is not for everyone. The following categories of people might need to take special precautions or weigh the options carefully when considering intermittent fasting for weight loss.

• Pregnant or lactating women
• People with a history of disordered eating (anorexia or bulimia)
• People with type 1 diabetes who are on insulin
• People with sleep problems, such as hypoglycemia, can further disrupt their sleep.
• People with a sensitive bowel, as the gut may react to the sudden presence of food
• Immunosuppressed
• People whose job requires intense energy, focus, and mental concentration

Other Dietary Approaches for Weight Loss

If you’d rather not adopt intermittent fasting for weight loss, here are other dietary approaches to lose weight healthfully.

1. Water fasting

As the name implies, this approach involves drinking only water for a given amount of time. This is especially beneficial when done synergistically with intermittent fasting.

2. Juice fasting

In this case, instead of drinking only water during the fasting period, one drinks fruit or vegetable juice instead. This helps to provide the body with supplemental glucose for energy generation.

3. Partial fasting

Partial fasting eliminates certain foods or drinks from your regular diet for a given amount of time. You may describe it as ‘selective fasting’ for some days, weeks, or months. For example, selectively excluding processed foods, sugar, caffeine, soda, or processed animal fats/products for an amount of time.

Diet in the Treatment of Diseases

In addition to weight loss and management of obesity, intermittent fasting is a dietary approach used for managing other systemic conditions, as mentioned earlier. However, intermittent fasting is not the only dietary approach adopted for these reasons. Here are other dietary approaches in the management and treatment of systemic diseases like hypertension, diabetes, etc.

1. The Mediterranean diet

The Mediterranean diet is a special dietary pattern that is based on the traditional diet of the countries bordering the Mediterranean Sea, which is highly protective and preventative of several chronic diseases, such as cardiovascular diseases (CVD). This diet is primarily focused on plant-based foods like fruits, vegetables, whole grains, legumes, nuts, seeds, and olive oil, with moderate amounts of fish, poultry, dairy, and limited red meat.

Several studies suggest that the Mediterranean diet reduces the risk of CVD by influencing endothelial function, inflammation, lipid profile, and blood pressure.^[14]Rovira J, Ramirez-Bajo MJ, Bañon-Maneus E, Ventura-Aguiar P, Arias-Guillén M, Romano-Andrioni B, Ojeda R, Revuelta I, García-Calderó H, Barberà JA, et al. Mediterranean Diet Pattern: Potential … Continue reading

2. The DASH diet

DASH stands for Dietary Approaches to Stop Hypertension. It was originally formulated by the National Institutes of Health (NIH), which highlights a comprehensive intake of nutrient-rich foods rich in potassium, magnesium, and fiber (fruits, veggies, whole grains) but low in sodium and saturated fats.^[15]Onwuzo C, Olukorode JO, Omokore OA, Odunaike OS, Omiko R, Osaghae OW, Sange W, Orimoloye DA, Kristilere HO, Addeh E, Onwuzo S, Omoragbon L. DASH Diet: A Review of Its Scientifically Proven … Continue reading

According to research, the DASH diet has shown profound efficacy in the reduction of hypertension, as well as addressing other related conditions like heart failure, dyslipidemia, and uric acid dysregulation, thus serving as an indispensable tool in the management of hypertension and cardiovascular-related conditions.

3. The Keto diet

The keto diet, or the ketogenic diet, is a low-carbohydrate, high-fat dietary plan in which the body is forced to utilize fat for energy instead of the traditional carbohydrate-first energy source. This leads to a metabolic state called ketosis, where fats are oxidized into ketone bodies, which are alternative sources of metabolic energy.

The ketogenic diet was first used by Russell Wilder in 1921 to treat epilepsy, where he observed that the diet reduced the frequency and intensity of seizures in some of his patients who adopted the diet. It is characterized by a reduction of carbohydrates to less than 50g daily. This decreases insulin secretion, leading to a catabolic state where ketone bodies from fats predominate as the major energy source.^[16]Masood W, Annamaraju P, Khan Suheb MZ, et al. Ketogenic Diet. Treasure Island (FL): StatPearls Publishing.

The ketogenic diet has shown remarkable benefits in the management of diabetes mellitus, epilepsy, or chronic seizure disorder. However, it may raise LDL cholesterol in some individuals and is not ideal for people with kidney disease or severe heart conditions.

4. Vegetarian diet

Involves total or partial restriction of animal-based foods. It is helpful for the prevention and treatment of heart disease, obesity, inflammatory diseases, and the prevention of cancer.^[17]Vegetarian and vegan eating – Better Health Channel, Victoria State Govt. Dept of Health

Vegetarians may require close vitamin and protein supplementation, e.g., vitamin B12, vitamin D, omega-3, and essential amino acids.

5. Anti-inflammatory diet

This focuses on anti-inflammatory foods like fatty fish, turmeric, berries, olive oil, dark chocolate, nuts, etc. They are based on the traditional diets of the Mediterranean and Asian cultures and are known to be rich in omega-3, vitamin C, polyphenols, fiber, etc, all of which are known to have strong anti-inflammatory properties.^[18]Anti Inflammatory Diet – Johns Hopkins Medicine^[19]Food as Medicine: Anti-Inflammatory Diet

6. Paleo Diet

For autoimmune conditions, weight loss, and metabolic health. It is rich in whole foods, grains, lean meats, nuts, seeds, fruits, and vegetables.

7. Gluten-free diet

A method of dietary restriction against gluten-rich foods (wheat, barley, rye) and replacing them with gluten-free alternatives. It is highly useful for those who have gluten sensitivity, Celiac disease, or inflammatory bowel syndrome (IBS).

Final words

As discussed in this article, intermittent fasting is a recommended dietary approach for the management and control of several metabolic and chronic medical conditions. The above tips show you how to adopt intermittent fasting for weight loss.

Other information contained here includes more information on dietary approaches in the management and control of some chronic systemic diseases.

As a rule, it is important to seek the services of your doctor if you are still unsure how to go about adopting any of these dietary approaches, and if you have more questions about whether or not IF is safe and how to achieve it.