Is 16-Hour Fasting Safe? The Overlooked Issue of "After Losing Weight" with Calorie Restriction

Why Do You Gain Back the Weight You Lost? The Pitfalls of "Calorie Restriction" and What You Need After Losing Weight

You finally lost weight by cutting down on meals, but as soon as you relax a bit, it comes back.

When this happens, it's easy to think, "I lack willpower" or "I failed at dieting again." However, weight changes are not determined by willpower alone. Appetite, energy expenditure, work and family circumstances, and the food around you all play a role.

In an article published by Cyprus Mail on November 14, 2026, nutrition experts Yasmin Probst and Olivia Wills from the University of Wollongong, Australia, discuss the effects and challenges of weight loss through calorie restriction.

What becomes clear is that focusing solely on "how to lose weight quickly" won't solve the problem of weight management. Instead, it's more important to consider what kind of eating habits to maintain after losing weight.

"Setting Meal Times" and "Reducing Calories" Are Not the Same

Calorie restriction involves reducing the energy intake from food and drinks. If the energy consumed is less than the energy expended, the stored energy in the body is used, leading to weight loss.

However, the necessary amount of energy varies from person to person. It changes based on age, body size, body composition, activity level, and health status, so simply mimicking someone else's diet is not advisable.

Moreover, methods that limit eating times, like the so-called "16-hour fasting," and methods that reduce calorie intake are technically different.

Some people may snack less or eat fewer late-night meals by shortening their eating window. On the other hand, if you eat a lot during the limited time, the total intake may not decrease sufficiently. It's difficult to judge the effect based solely on "how many hours you didn't eat."

A 12-month randomized controlled trial published in 2022, involving 139 obese individuals, compared a group with calorie restriction plus time-restricted eating to a group with calorie restriction alone. Both groups lost weight, but there was no statistically significant difference in the amount of weight loss.

This study alone does not negate the effectiveness of all time-restricted eating. However, it cannot be said that "narrowing the eating window will definitely lead to more weight loss than the same calorie restriction."

Consuming Less Than 800 Calories a Day Is Not a Casual Challenge

The term "calorie restriction" encompasses everything from relatively mild adjustments to strict dietary therapies conducted under medical supervision. It's important not to overlook these differences.

The original article introduces "very low-energy diets," which typically involve reducing daily energy intake to less than 800 calories. This is not a guideline for the general public to undertake on their own.

The UK's NICE positions this method as something to be considered as part of specialized services for individuals with obesity who require rapid weight loss for clinical reasons, such as improving surgical safety.

Additionally, it requires meeting nutritional needs, limiting the implementation period to 12 weeks, and receiving continuous medical support and advice on returning to a regular diet.

Simply reducing food intake drastically does not equate to the dietary therapies used in medical settings. Focusing only on the result of "losing a lot in a short period" can obscure the selection of subjects and nutritional management behind it.

Why You Can't Blame Rebound on "Lack of Willpower"

When you lose weight, your body is no longer under the same conditions as before.

As your weight decreases, the energy required to maintain and move your body also changes. Additionally, physiological adaptations to weight loss may increase appetite or suppress energy expenditure.

A report from a workshop by the U.S. National Institute of Diabetes and Digestive and Kidney Diseases also addresses these changes in appetite and metabolism as factors that make maintaining weight after weight loss difficult.

Even if you think you're making the same effort, you may not lose weight at the same rate as before. You may feel hungrier than before. These changes are not necessarily "proof of losing motivation."

However, this is not the same as the explanation often shared on social media that "once you enter starvation mode, you can't lose weight no matter what." There are individual differences in body responses, and it's impossible to explain weight stagnation with a single term.

The problem is thinking that all stagnation is due to your own weakness and further reducing your food intake. If severe hunger persists and affects your sleep, mood, and enjoyment of meals, it's necessary to review your approach rather than intensifying restrictions.

The Anxiety on Social Media About "Needing to Count Calories for Life"

The confusion about life after weight loss is also evident on social media overseas.

The discussion here is not a direct reaction to the original article but rather a debate on rebound and weight maintenance published in the Reddit weight loss community "r/loseit." These are personal experiences and do not represent research-verified effects or the overall public opinion.

One poster expressed anxiety about being able to maintain their weight after reaching their goal, as they returned to their previous eating habits during a trip, despite having meticulously recorded calories to lose weight.

This post received replies from different perspectives.

For Some, Keeping Records Provides Reassurance

One reply suggested that even after reaching the target weight, planning is necessary, and the idea of switching to a maintenance diet rather than a weight loss diet was presented.

Although they dislike recording calories, they continue to do so because much of the weight they previously lost has returned.

For this person, keeping records is not just a tool for endurance but a means to understand their food intake.

Some Stop Calculating and Use Meal Patterns

On the other hand, a user who hasn't recorded calories for several years explained that they estimate their food intake by maintaining a certain structure in home-cooked meals and swapping ingredients within the same category.

Another reply pointed out that eating a lot during a trip doesn't necessarily determine future rebound. The focus should be on daily habits repeated at home or work, not just occasional trips.

These exchanges reveal that the burden of weight maintenance and the methods that are easy to use vary from person to person.

For some, recording numbers brings peace of mind, while for others, calculating meals every time becomes a burden. There is no single correct answer for everyone.

In the Context of Japanese Dining, Review Meal Composition Before "Reducing"

So, when organizing daily eating habits in Japan, what should be the focus?

The experts in the original article emphasize the importance of the overall quality of the diet and sustainable habits over drastically cutting calories. They also mention the importance of consuming enough protein and incorporating foods rich in dietary fiber, such as vegetables, legumes, and whole grains.

Translating this to Japanese dining, it might be considered as follows:

Don't Try to Solve Everything by Cutting Out Rice

Simply reducing the staple food doesn't necessarily balance the nutrition or satisfaction of the entire meal.

How to combine main dishes like fish, meat, eggs, and soy products with side dishes like vegetables. It's more practical to first look at the entire menu and consider the amount that suits you.

Instead of increasing the list of "foods you can't eat," it's important to check if anything necessary is missing.

Decide on Options for Busy Days

An ideal menu that can only be prepared on days with time won't last on busy days with overtime or household chores.

For example, combining eggs or tofu with staple foods, keeping frozen vegetables on hand, or finding menus that offer both main dishes and vegetables when eating out. This is not a method that guarantees specific weight loss effects but an example of incorporating the original article's suggestion to "plan meals in advance" into daily life.

It's easier to have a few meal options ready rather than deciding what to eat from a state of hunger each time.

Consider Habits Beyond Meals

Sweet drinks, alcohol, and snacks eaten out of habit are also part of the diet. Before cutting down on staple foods or main dishes, it's important to reflect on what can be adjusted in daily life.

At the same time, it's important to focus on enjoyable physical activities and pay attention to feelings of hunger and fullness. This approach prevents concentrating the burden solely on meals.

"Effective in the Short Term" and "Meaningless in the Long Term" Are Different

The original article explains that many studies on calorie restriction are short-term and that maintaining weight loss is difficult.

However, concluding from this that "there's no point in trying because you'll regain the weight anyway" is not accurate.

NICE's rationale explanation includes studies where the effects of low-energy and very low-energy diets continued for 3-5 years under conditions of continuous support.

What kind of diet to transition to after the short-term dietary restriction ends. Who to consult when weight begins to return. Whether it can be adjusted to a method that can be sustained in real life.

It's necessary to consider not only the name of the weight loss method but also the support that follows. It's important not to separate "the period of losing weight" and "life afterward" as separate issues.

Before Starting, Confirm Whether You Need to Lose Weight

Diet articles as health information should not be read as a message that everyone needs to lose weight.

The original article states that such restrictive diets are not recommended for pregnant or breastfeeding individuals, children or young people without professional supervision, or those with a history of eating disorders. If you have chronic illnesses or are on medication, it's advisable to consult a doctor or registered dietitian before proceeding with strict restrictions on your own.

Even for those who need to lose weight, the goal is not just the number on the scale.

Are you irritable all day due to hunger? Are you enjoying your meals? Do you have the energy to handle work and household chores? Can you continue this method even on busy days?

Focusing on "what kind of life it has become" is as important as "how many kilos lost" in finding a sustainable way of eating.

Even when weight returns after losing it, there's no need to judge your character. It should be treated as an opportunity to review the amount and content of meals, living environment, and how support is received.

The question to consider before starting is not "how long can you go without eating," but "what kind of eating can you continue without difficulty six months from now."

Sources and References

1. Cyprus Mail/The Conversation "What are calorie-restricted diets?"
   Published on November 14, 2026. An explanation by Yasmin Probst and Olivia Wills on the effects of calorie restriction, the difficulty of maintaining weight, and improving eating habits.
   https://cyprus-mail.com/2026/11/14/what-are-calorie-restricted-diets

2. NICE "Overweight and obesity management: Physical activity and diet"
   Guidelines from the UK on the target, implementation period, nutritional management, and professional support for low-energy and very low-energy diets.NICE
   https://www.nice.org.uk/guidance/ng246/chapter/Physical-activity-and-diet

3. NICE "Overweight and obesity management: Rationale and impact"
   Explanation of the rationale for long-term effects and support for transitioning to post-weight-loss diets under continuous support.NICE
   https://www.nice.org.uk/guidance/ng246/chapter/Rationale-and-impact

4. "Calorie Restriction with or without Time-Restricted Eating in Weight Loss"
   Published in 2022. A 12-month randomized controlled trial comparing the effects of adding time-restricted eating to calorie restriction in 139 obese individuals.pubmed.ncbi.nlm.nih.gov
   https://pubmed.ncbi.nlm.nih.gov/35443107/

5. "Physiology of the Weight Reduced State"
   A report from a workshop by the U.S. NIDDK. It organizes physiological factors that make maintaining weight after weight loss difficult, such as changes in appetite and energy expenditure.PMC
   https://pmc.ncbi.nlm.nih.gov/articles/PMC8978330/

6. Reddit "r/loseit" Public Thread on Anxiety About Weight Maintenance and Rebound
   Refers to anxiety about returning to previous eating habits during travel, the idea of continuing calorie recording, and experiences of maintaining with meal patterns. The text summarizes the post content in Japanese and is not a direct reaction to the original article.reddit.com
   https://www.reddit.com/r/loseit/comments/1t4chuc/why_i_might_end_up_regaining_all_my_weight_once/