Intermittent fasting for weight loss: A comprehensive guide

Losing weight can be approached in various ways.

Recently, many folks have taken up intermittent fasting as a method.

Intermittent fasting is a way of eating where you go through regular, brief fasts, meaning you eat very little or not at all for short periods.

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Lose weight

Gain muscles

Eat healthy

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A lot of people see intermittent fasting mainly as a way to shed pounds. When you fast for short durations, you often consume fewer calories, which could lead to weight loss over a while.

But, it’s not just about weight. Intermittent fasting might also play a role in improving health markers linked to conditions like diabetes and heart issues, such as by reducing cholesterol and blood sugar levels.

This article dives deep into all you should understand about intermittent fasting and its role in weight loss.

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Choosing your intermittent fasting plan

Various intermittent fasting methods are out there. Some of the most favored ones are:

The 16:8 method
The 5:2 diet
The warrior diet
“Eat Stop Eat”
Alternate-day fasting (ADF)

Each method has its benefits, but the right one for you depends on your personal preferences.

Here’s a simple guide detailing the advantages and drawbacks of each to assist you in finding the perfect fit for your way of life.

The 16/8 approach

The 16/8 method is a favorite way of intermittent fasting to shed pounds.

In this approach, you’re limited to eating and having calorie-laden drinks within an 8-hour window daily. The rest of the 16 hours, you’re to avoid any food.

Unlike some diets with hard-set rules, the 16/8 approach is based on time-restricted feeding (TRF) and offers more leeway.

You can pick any 8-hour slot to have your meals.

Many decide to pass on breakfast, eating from noon to 8 p.m. Some choose an early window, like 9 a.m. to 5 p.m.

By narrowing down your eating hours, you might find it easier to lose weight and even experience a drop in blood pressure.

Studies suggest time-bound eating patterns like the 16/8 can combat high blood pressure and decrease overall food intake, aiding weight loss.

A study in 2016 showed that pairing this method with muscle-building exercises reduced body fat and kept muscles intact in male participants.

16/8 intermittent fasting: A beginners guide

Another study discovered that the 16/8 approach didn’t hinder muscle or strength gains in women who did resistance exercises.

But remember, sticking to 16 hours without food can be tough for some.

Also, if you indulge in too much unhealthy food during your 8-hour period, it might cancel out the benefits of this fasting method.

Aim for a nutritious diet that includes fruits, veggies, whole grains, healthy fats, and proteins to truly reap this method’s health rewards.

The 5:2 diet

The 5:2 plan offers a simple way to intermittent fast.

For five days a week, you eat as you normally would without counting calories. However, on the remaining two days, you cut your daily calorie intake to just a fourth.

For someone typically having 2,000 calories daily, they’d take in only 500 calories on those two fasting days.

A 2018 study suggests the 5:2 method is as effective as reducing calories daily when it comes to weight loss and managing blood sugar in type 2 diabetes patients.

Another research piece found the 5:2 method to be as beneficial as consistent calorie-cutting for weight loss and preventing conditions like heart diseases and diabetes.

The 5:2 plan offers flexibility: you choose your fasting days, and there’s no hard rule about what or when to eat on regular-calorie days.

However, “eating normally” doesn’t mean binging. It’s vital to strike a balance.

Sticking to just 500 calories on the fasting days might be tough and, if not done right, could leave you feeling weak or dizzy.

While the 5:2 method has its merits, it’s not suitable for everyone. It’s best to chat with a healthcare professional before diving in.

“Eat Stop Eat” method

“Eat Stop Eat” is a distinct way of intermittent fasting brought to light by Brad Pilon in his book of the same name.

In this approach, you pick one or two separate days in the week to fast for a whole 24 hours.

For the other days, while you’re free to eat, it’s wise to have a balanced diet and not overeat.

The core idea here is that reducing calorie intake can help in weight loss.

Going without food for 24 hours can shift your metabolism, prompting your body to use stored fat for energy instead of sugar.

However, holding off from eating for a whole day tests your determination and might lead to eating excessively afterward. It could also set the stage for unhealthy eating habits.

There’s still a need for more studies on the “Eat Stop Eat” approach to gauge its health and weight loss benefits fully.

If you’re considering this method, it’s essential to consult with a healthcare expert to see if it’s a suitable weight loss strategy for you.

Alternate-day fasting

The structure of alternate-day fasting is pretty straightforward. Here, you avoid eating every alternate day, but on non-fasting days, there’s no set limit on your food intake.

Some variations of this method allow about 500 calories on fasting days, while others promote complete fasting.

There’s good evidence supporting weight loss with alternate-day fasting.

One study, comparing this method to everyday calorie cutting in obese adults, found both ways equally effective for weight loss.

Another piece of research noted that people ate 35% fewer calories and shed about 7.7 pounds (3.5 kg) after alternating between 36 hours of fasting and 12 hours of unrestricted eating for a month.

To optimize weight loss further, adding some form of physical activity helps.

Studies have found that merging alternate-day fasting with aerobic exercises might double the weight loss compared to just fasting.

But fasting fully every other day can be demanding, particularly for beginners. And there’s always the lure to overeat on non-fasting days.

Starting with a less stringent fasting plan might be a good step if you’re new to this practice.

Regardless of how you approach it, prioritizing a healthy diet filled with protein-rich foods and low-calorie veggies will keep you feeling satisfied.

The warrior diet

The warrior diet takes inspiration from ancient warrior eating habits.

Devised in 2001 by Ori Hofmekler, this method is somewhat stricter than the 16:8 approach but more lenient than “Eat Stop Eat.”

Here, you eat minimally for 20 hours a day, and then for 4 hours in the evening, you can have a hearty meal.

During the 20-hour fasting period, it’s suggested to have small servings of dairy, hard-boiled eggs, raw fruits and veggies, and calorie-free drinks.

Post this 20-hour fast, you have a 4-hour window where you’re encouraged to eat mainly wholesome, organic foods, though there’s flexibility.

While specific studies on the warrior diet are limited, research has shown that time-bound eating can contribute to weight loss.

There are also potential health advantages to time-restricted eating, with findings indicating its potential in preventing diabetes, slowing down tumor growth, anti-aging effects, and even boosting lifespan in animals.

More in-depth research on the warrior diet is required to discern its full weight loss benefits.

The strict 20-hour fasting can be challenging for many, and there’s a temptation to overeat during the 4-hour eating window.

The warrior diet might also pave the way for unhealthy eating habits. Before attempting this, consulting a health professional to ensure it aligns with your health goals is crucial.

Summary: Intermittent fasting comes in multiple forms, each having its own set of advantages and hurdles. Before choosing any, discussing it with your doctor will help determine the best fit for you.

Hormonal adaptations with intermittent fasting

The human body is incredibly adaptable, responding to various conditions to maintain homeostasis. Fasting or reducing calorie intake triggers a cascade of hormonal adaptations designed to facilitate energy mobilization and conservation.

Intermittent fasting is not just about reducing calorie intake; it’s about the hormonal responses it induces, which can have profound effects on metabolism.

Here’s a breakdown of how intermittent fasting affects specific hormones:

Insulin: Insulin is a hormone released by the pancreas to help cells take in glucose for energy. After meals, especially carbohydrate-rich ones, insulin levels rise. But during fasting periods, insulin levels drop. This decrease in insulin levels aids in promoting the mobilization of stored fat for energy.
Norepinephrine (noradrenaline): This hormone is both a neurotransmitter in the nervous system and a hormone in the bloodstream. During fasting, there’s an increase in the release of norepinephrine. This boost sends signals to fat cells, instructing them to release stored fat, which can then be utilized as an energy source.
Human growth hormone (HGH): HGH plays pivotal roles in growth, metabolism, and muscle strength. Short-term fasting can induce a significant increase in HGH production. Historically, increased HGH was thought to aid in fat metabolism, but recent research indicates a more complex role. Elevated HGH might signal the brain, specifically AgRP neurons, to conserve energy, potentially making prolonged weight loss more challenging. This adaptation might have been evolutionarily beneficial, conserving energy during periods of scarcity.

The interplay between these hormones and others, like ghrelin (hunger hormone) and leptin (satiety hormone), determines hunger, energy utilization, fat storage, and overall metabolism. While short-term intermittent fasting may promote fat burning, the long-term hormonal responses are more intricate and need further exploration.

8 science-backed health benefits of fasting

Summary: Intermittent fasting induces a myriad of hormonal changes designed to mobilize energy. While some hormones like insulin and norepinephrine aid in fat mobilization, others like HGH might have a dual role, aiding in fat metabolism but also signaling energy conservation, making prolonged weight loss a complex endeavor.

Intermittent fasting leads to calorie reduction and consequent weight loss

The primary mechanism behind intermittent fasting’s effectiveness for weight loss is its inherent reduction in calorie consumption.

By skipping certain meals during the fasting window, you typically end up eating less unless you significantly overeat during the eating windows.

A review from 2014 found that people practicing intermittent fasting experienced a 3–8% weight reduction over a span of 3–24 weeks.

In terms of the pace of weight loss, it’s estimated that intermittent fasting can lead to a weight loss rate of around 0.55 to 1.65 pounds (0.25–0.75 kg) each week.

A notable 4–7% decrease in waist circumference was observed, pointing towards a loss of belly fat.

These findings suggest that intermittent fasting stands as an effective method for weight reduction.

However, intermittent fasting’s advantages aren’t solely limited to weight loss. It also offers multiple metabolic health benefits and may even play a role in decreasing cardiovascular disease risk.

Though intermittent fasting often obviates the need for meticulous calorie counting, its weight-reducing effect mainly stems from a reduction in overall calorie intake.

Comparative studies between intermittent fasting and consistent calorie restriction indicate that when caloric intake is equal, there’s no discernible difference in weight loss outcomes.

Summary: Intermittent fasting presents a practical approach to weight loss without the rigidity of calorie counting. Multiple studies have demonstrated its efficacy in facilitating weight and belly fat loss.

Intermittent fasting could potentially preserve muscle during weight loss

One of the pitfalls of dieting is the simultaneous loss of muscle along with fat.

Suggested read: Top 23 weight loss tips for women

Some studies suggest that intermittent fasting might be advantageous in preserving muscle while shedding fat.

An analytical review determined that intermittent calorie restriction led to similar weight loss outcomes as continuous calorie restriction, but with a significantly less pronounced decrease in muscle mass.

In the continuous calorie restriction scenarios, muscle mass accounted for 25% of the total weight loss, whereas in the intermittent calorie restriction, it constituted just 10%.

Nonetheless, these studies come with certain limitations, so it’s prudent to interpret the results cautiously. More contemporary research hasn’t detected any significant distinction in lean or muscle mass when comparing intermittent fasting to other dietary approaches.

Summary: There is some preliminary evidence hinting that, in comparison to traditional calorie restriction, intermittent fasting might be better at preserving muscle mass. However, newer research hasn’t consistently validated this hypothesis.

Intermittent fasting simplifies healthy eating choices

One major advantage of intermittent fasting is how straightforward it is.

Instead of focusing on calorie counting, most intermittent fasting plans just ask you to watch the clock.

Choosing a diet pattern that’s sustainable for you in the long-term is crucial. If intermittent fasting simplifies your healthy eating habits, it can offer lasting benefits for health and weight management.

Summary: Intermittent fasting simplifies the process of making healthy food choices, potentially making it more sustainable for long-term health and weight goals.

Tips for succeeding with intermittent fasting

If you’re aiming for weight loss through intermittent fasting, remember these key points:

Food quality matters. Opt for whole foods that have a single ingredient.
Monitor your calories. During non-fasting times, eat regular amounts and avoid overcompensating for the fasting period.
Stay committed. Like any weight-loss strategy, longevity and consistency are key.
Give it time. Your body might need a while to get used to intermittent fasting. Sticking to a regular eating schedule can help.

Many popular intermittent fasting plans also advocate for activities like strength training. This is crucial to primarily burn fat while preserving muscle.

Initially, you may not need to count calories when practicing intermittent fasting. But if you hit a plateau in weight loss, keeping track of calories can be helpful.

Summary: When practicing intermittent fasting, it’s essential to eat nutritious foods and maintain a calorie deficit. Consistency and regular exercise play vital roles in achieving your goals.