What is the 5 day reset diet that blasts belly fat?

October 9, 2025 •

5 min read

According to research published by the National Institutes of Health (NIH), a 5-day fasting regimen can lead to substantial reductions in body mass, fat mass, and waist circumference, but the idea of a 'reset diet that blasts belly fat' is a marketing concept based on the temporary nature of rapid weight loss. These plans often rely on severe calorie restriction, which can cause significant changes over a short period, but not without potential downsides.

Quick Summary

Several types of 5-day reset diets exist, from fasting-mimicking and commercial kits to post-surgery plans. The concept of 'blasting belly fat' is medically unfounded, as targeted fat loss is impossible; rapid weight reduction is largely due to water and muscle loss, not sustainable fat loss. Restrictive resets carry risks like nutrient deficiencies and weight regain, making a balanced, long-term approach safer and more effective for lasting health.

Key Points

Spot Reduction is a Myth: You cannot target fat loss in a specific area like the belly with a diet or exercise regimen.
Rapid Weight Loss is Mostly Water: The quick weight loss from a restrictive 5-day diet is primarily water and muscle loss, not sustainable fat loss.
Multiple 5-Day Resets Exist: The term refers to different plans, including fasting-mimicking diets (FMD), bariatric resets, and commercial kits, not one standardized method.
Risks of Restrictive Diets: Severe calorie restriction can lead to weight regain, nutrient deficiencies, fatigue, and an unhealthy relationship with food.
Sustainability is Key: Long-term fat reduction, including belly fat, is best achieved through a balanced diet, regular exercise, and consistent, healthy lifestyle habits.
Consult a Professional: Always speak with a healthcare provider before starting any restrictive diet, especially if you have underlying health conditions.

The promise of a quick, five-day fix for stubborn belly fat is highly appealing in today's fast-paced world. Many different diets claim to offer this 'reset,' from intermittent fasting variations to pre-packaged meal plans. But what do these diets actually involve, and do they live up to their bold promises? The truth is more complex than the headlines suggest, with medical experts highlighting that spot reduction is not possible and that sustainable results require a long-term commitment.

Unpacking the Different “5-Day Reset” Diets

Due to the popularity of the term, there is no single, standardized '5-day reset diet.' Instead, the phrase refers to several distinct protocols:

The Fasting-Mimicking Diet (FMD)

Developed by Professor Valter Longo, the FMD protocol involves a short-term, very low-calorie diet for five days that tricks the body into thinking it is fasting. A commercial version, ProLon, provides pre-packaged food for the five days. The diet claims to trigger cellular rejuvenation and target abdominal fat loss without significant lean muscle loss.

Bariatric Pouch Reset

For individuals who have undergone bariatric surgery, a '5-day pouch reset' is a diet program designed to get them back on track after experiencing weight loss plateaus or regaining weight. This highly specific, structured diet is intended to re-train the stomach pouch to accept smaller food portions and is strictly for post-op patients under medical supervision.

The Commercial Kit Reset

Numerous wellness brands offer pre-packaged 5-day 'resets.' These often provide shakes, supplements, and snacks intended to curb hunger and provide nutrients during a short period of calorie control. While convenient, these are often repetitive, can be expensive, and may not teach sustainable, long-term healthy eating habits.

The General “Cleanse” or “Detox” Approach

Many informal versions exist, focusing on the consumption of smoothies, juices, or highly restrictive food lists for five days. These are typically aimed at 'detoxifying' the body, a process that is naturally and efficiently handled by the liver and kidneys. Weight loss is often a result of water loss and an extreme calorie deficit.

The Myth of “Belly Fat Blasting” in 5 Days

While these diets can lead to a quick drop in the number on the scale, the claim of 'blasting belly fat' is misleading. Here’s why:

Spot Reduction is a Myth: It is not physically possible to choose where your body loses fat. When you lose weight through a calorie deficit, your body reduces fat stores from all over, with genetics determining the distribution.
Temporary Weight, Not Fat Loss: Much of the rapid weight loss seen in the first few days of a restrictive diet is not fat but water weight and glycogen stores. Your body stores carbohydrates with water, and as those stores are depleted, you lose that water weight.
Risk of Muscle Loss: Extreme calorie restriction can cause the body to break down lean muscle tissue for energy, especially if protein intake is insufficient. This can lower your metabolic rate, making it easier to regain weight once the diet is over.

Risks of Restrictive 5-Day Resets

Restrictive, short-term diets, especially those involving severe calorie deficits, carry a number of risks:

The Rebound Effect: Most people who complete a short, restrictive diet regain the lost weight, and sometimes even more, after returning to their normal eating patterns. This is a result of the metabolic slowdown and the psychological toll of restriction.
Nutrient Deficiencies: Severely limiting food choices can result in a lack of essential vitamins, minerals, healthy fats, and fiber. While a multi-vitamin can help, getting nutrients from whole foods is always preferable.
Negative Side Effects: Fasting days or severe restriction can cause fatigue, headaches, irritability, and poor concentration.
Disordered Eating: Relying on short-term fixes can lead to an unhealthy relationship with food, with cycles of restrictive dieting followed by binge eating.
Not for Everyone: These diets are generally not safe for pregnant or nursing women, individuals with a history of disordered eating, or people with unmanaged diabetes or other chronic health conditions. A healthcare provider should always be consulted before starting.

Comparison: Quick Fix vs. Sustainable Approach


Feature	Quick Fix 5-Day Reset (e.g., detox)	Sustainable, Healthy Approach
Goal	Rapid, temporary weight loss; 'detoxification'	Slow, steady, long-term fat loss and improved health
Focus	Short-term severe calorie restriction; liquids	Long-term lifestyle changes; balanced nutrition
Weight Loss	Primarily water and muscle; quick and temporary	Primarily fat; gradual and lasting
Health Impact	Risk of nutrient deficiencies, fatigue, rebound weight gain	Improved metabolism, better energy levels, overall well-being
Dietary Habits	Often highly restrictive and unsustainable	Teaches moderation, variety, and mindful eating
Cost	Can be very expensive (kit-based resets)	Usually more affordable, focusing on whole foods

A Safer, More Sustainable Path to Health

For genuine and lasting results, focus on incorporating sustainable habits into your daily life. This includes:

A Balanced Diet: Emphasize whole, nutrient-dense foods like fruits, vegetables, lean proteins, legumes, and healthy fats.
Portion Control: Learn to listen to your body’s hunger and fullness cues to manage calorie intake without severe restriction.
Consistent Exercise: Combine cardio with strength training. Exercise builds muscle, boosts metabolism, and is a proven way to reduce overall body fat, including abdominal fat.
Hydration: Drink plenty of water throughout the day to support metabolism, aid digestion, and help you feel full.
Stress Management: High stress levels can increase cortisol, a hormone linked to increased belly fat. Finding healthy ways to cope, like yoga or meditation, can help.

Conclusion: Focus on Long-Term Health

The appeal of a quick-fix diet, like a '5 day reset that blasts belly fat,' is undeniable, but the reality is that targeted, rapid fat loss is a myth. While various 5-day protocols exist, they often result in temporary weight changes, not sustainable fat loss, and can carry risks. For genuine and lasting improvements in health and body composition, focus on the consistent, evidence-based practices of a balanced diet, regular exercise, and long-term lifestyle changes. Remember to always consult a healthcare professional before beginning any new diet plan.

For more detailed information on intermittent fasting techniques like the 5:2 diet, the Cleveland Clinic offers a comprehensive guide, but always discuss with a professional first.

Frequently Asked Questions

No, a 5-day reset diet will not 'blast' belly fat. While you may lose some weight due to a calorie deficit, it is medically impossible to target fat loss in one specific area of the body. Any rapid weight loss is mainly water and muscle mass.

A Fasting-Mimicking Diet (FMD) is a specific, very low-calorie protocol developed by Professor Valter Longo to induce the effects of fasting while still consuming some food, potentially sparing lean muscle. A general 'detox' or 'cleanse' is often an informal, highly restrictive diet (sometimes liquid-based) with unproven health claims about eliminating toxins.

Safety depends on the specific diet and your health status. Extremely restrictive versions can be unsafe, especially for pregnant or nursing women, or those with certain medical conditions. Always consult a doctor before starting to ensure it is appropriate for you.

Most of the weight lost on a short, restrictive diet is water weight and depleted glycogen stores. Some muscle mass may also be lost, especially with insufficient protein intake. Minimal actual body fat is lost in such a short period.

After the restrictive period, many people experience a rebound effect, regaining the lost weight, and sometimes more. This is because the body slows its metabolism and increases appetite signals after a period of deprivation.

A healthier, more sustainable approach involves a balanced diet of whole foods, regular exercise combining cardio and strength training, staying hydrated, and managing stress. This leads to gradual, lasting fat loss and improves overall health.

Commercial kits may offer a structured, convenient experience, but they are less likely to teach you long-term, sustainable eating habits. They can also be expensive and lead to dependency on the product rather than on making healthy food choices yourself.