All Good Things Come in Threes: Why the 4:3 Diet Wins

They say all good things come in threes, and when it comes to dieting, this wisdom seems to hold true. Finding a diet that’s effective, sustainable, and fits into your life is no small feat. Many diets either demand too much or deliver too little, leaving you frustrated or burned out. Among the myriad of intermittent fasting strategies, the 4:3 diet—fasting for three days a week with up to 1,000 calories on fasting days and eating normally on the other four—stands out as the Goldilocks solution. It’s not too restrictive, not too lenient, but just right. Let’s break down why the 4:3 diet is the long-term winner by comparing it to other fasting schedules, with a clear list of their downsides, backed by science and insights into human behavior.

The Challenge of Finding Balance

Dieting is a delicate balance of effort and reward. Too little effort, and you won’t see results; too much, and you’re likely to quit. Research on habit formation shows that overly demanding regimens lead to high dropout rates. A 2018 study in Health Psychology found that individuals with overly ambitious goals, like exercising daily, were more likely to abandon their efforts within three months compared to those with moderate goals, like three times a week. The reason? Excessive frequency creates a sense of burden, draining motivation. Diets that demand too much, too often, suffer the same fate, as people quit when the effort feels overwhelming.

Conversely, moderate, consistent efforts are more sustainable. A 2017 study in Medicine & Science in Sports & Exerciseshowed that exercising three days a week led to better long-term adherence than five or more days, as the rest days provided physical and mental recovery. The 4:3 diet aligns with this principle, offering enough fasting to drive results while allowing ample normal eating days to keep you motivated and recovered.

Just as important, the non-consecutive structure of the 4:3 diet—where you can fast on, say, Monday, Wednesday, and Friday—means you never go more than one day without eating normally. That psychological relief is crucial. Other plans don’t offer that flexibility. Let’s examine the downsides of other fasting schedules and why they fall short by comparison.

Comparing Fasting Schedules: The Downsides

Here’s a breakdown of the different fasting schedules, highlighting why each one—except the 4:3 diet—misses the mark:

1 Day Diet

Fasting for just one day a week sounds easy, but it’s too minimal to deliver meaningful results. The calorie deficit is small, leading to negligible weight loss or health benefits. It’s like starting a book but only reading the first chapter—you don’t get far enough to feel satisfied. For most, the lack of visible progress saps motivation, making it hard to stick with the plan long-term.

2 Day Diet

A two-day fasting schedule, such as the popular 5:2 diet, is a step up but still falls short of the desired impact. While it creates a larger calorie deficit than a one-day fast, the results often feel underwhelming for the effort. Two days of restriction don’t provide enough time to tap into fat stores effectively, leaving you wanting more progress without the structure to achieve it. Though non-consecutive fasting is possible, many people find it difficult to establish real momentum.

3 Day Diet (4:3 Diet)

This is the sweet spot. Fasting for three days a week, with up to 1,000 calories on fasting days, delivers significant results without overwhelming you. The flexibility to choose non-consecutive fasting days (e.g., Monday, Wednesday, Friday) accommodates busy schedules and social lives. This built-in rest structure helps keep motivation high and fatigue low.

Studies, like one from The American Journal of Clinical Nutrition (2020), show that three-day fasting schedules lead to notable weight loss and improved insulin sensitivity, with high adherence rates due to the balance of fasting and normal days. People are more likely to stick with a diet that feels manageable and doesn’t dominate their week.

4 Day Diet

Fasting for four days a week tips the balance toward restriction. While it can be effective, it becomes nearly impossible to structure the fasting days non-consecutively without placing them back-to-back. This lack of flexibility means you're fasting almost every other day or stringing fasts together, which reduces psychological and physical recovery time. The inability to spread out fasting days contributes to diet fatigue, and studies like a 2021 Nutrients article note that more restrictive diets had dropout rates as high as 65% within six months.

5 Day Diet

A five-day fasting schedule leaves only two normal eating days, which feels overly restrictive for most. More critically, you cannot distribute fasting days non-consecutively—you’re essentially in a constant state of calorie restriction for most of the week. This structure allows no true “off” days between fasts, reducing your ability to recover both mentally and physically. Social meals, family dinners, and weekends become difficult to enjoy, which leads to feelings of deprivation and frustration. Research in Nutrients (2021) supports that diets with limited recovery time have notably low adherence rates.

6 Day Diet

Fasting for six days a week is grueling and leaves just one day to eat normally. Not only is this nearly impossible to do non-consecutively, it’s also unsustainable from a lifestyle perspective. With no flexibility, no real rest, and no breathing room, this approach feels more like a punishment than a diet. The constant restriction can lead to both physical exhaustion and psychological burnout, making it incredibly difficult to maintain long-term. Studies on extreme diets show that such intensity leads to high dropout rates due to overwhelming demands.

7 Day Diet

Fasting every day is the ultimate test of willpower—and for most, it’s entirely unsustainable. With no normal eating days, it’s less a diet and more a form of prolonged self-denial. There is zero room for recovery, no non-consecutive planning possible, and no psychological relief. The lack of balance makes it feel like a constant battle, and research on habit formation, like Charles Duhigg’s The Power of Habit, emphasizes that habits requiring daily effort without breaks are the least likely to stick. People need rest days to stay motivated and committed.

Why the 4:3 Diet Shines

The 4:3 diet stands out because it balances effort and reward while offering the flexibility to plan around your life. Allowing up to 1,000 calories on fasting days makes the restriction manageable—you’re not starving, but you’re still creating a calorie deficit. The three-day structure provides enough fasting to drive meaningful weight loss and health benefits, as supported by a 2019 study in Obesity, which found that three-day-a-week fasting led to sustained weight loss over six months with high participant satisfaction.

The ability to choose non-consecutive fasting days—for example, avoiding weekends or holidays—makes the 4:3 diet uniquely livable. This adaptability reduces the sense of burden, allowing the diet to feel like a choice rather than a chore.

Science supports the power of three-day schedules. A 2020 study in The American Journal of Clinical Nutrition found that intermittent fasting with three fasting days per week improved metabolic markers and weight loss while maintaining high adherence. The rest days between fasting periods provide recovery, both physically and mentally, which aligns with research on habit formation. For example, exercising three days a week is often cited as the minimum effective dose for fitness gains, with rest days fostering long-term commitment (Medicine & Science in Sports & Exercise, 2017). The 4:3 diet follows this same principle—offering enough challenge to drive results and enough rest to keep you engaged.

The Long-Term Winner

The 4:3 diet isn’t just about fasting—it’s about building a sustainable habit. Its three-day structure delivers results without overwhelming you, while the four normal days let you enjoy life without guilt. The flexibility of non-consecutive fasting days makes it practical, fitting into real-world schedules with ease. Most importantly, it avoids the burnout and fatigue that come from plans that are too frequent or too rigid.

Science confirms that moderate, consistent efforts—like fasting three days a week—are more likely to stick, as they balance challenge with recovery. This makes the 4:3 diet not only effective, but enjoyable enough to maintain in the long run.

In the end, the saying “all good things come in threes” proves true for dieting. The 4:3 diet is the long-term winner because it respects your body, your mind, and your lifestyle. Whether you’re aiming to lose weight, boost health, or find a plan you can stick with, the 4:3 diet shows that three days a week is the magic number for lasting success.