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Is the 80/20 rule healthy? The pros and cons of the diet plan

The 80/20 rule diet is balanced and flexible and can help you lose weight. But there are some downsides to be aware of.

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The 80/20 rule is simple. Eat nutritious, healthy foods 80% of the time and enjoy foods considered less healthy 20% of the time. It's a more flexible approach to eating, which encourages a balanced diet and indulging in moderation rather than restrictive dieting.

Whether your goal is losing weight, boosting energy, or preventing disease — changing your diet is no easy task. Committing to making healthy choices every single meal, every single day, can be daunting. But it's not necessary, according to the 80/20 philosophy.

The 80/20 plan is about consistency. It's rooted in the idea that what you do most of the time has the greatest impact. It's more of a real-life approach to healthy eating — because real life involves treating yourself, sometimes with a cherry on top.

If you don't want to deprive yourself of your favorite treats and like the idea of enjoying junk food or sweets every now and then while maintaining a nutritious diet, the 80/20 plan might be a good option. Here’s how it works and how to determine if it’s the right fit for you.

80/20 rule: Here’s what to eat 80% of the time

Most of the time, you’ll be filling your plate with whole foods. It’s healthiest to load about ¾ of your plate with plant foods, such as vegetables, fruit, nuts, seeds, beans, whole grains and extra virgin olive oil.

That leaves a quarter of your plate for animal foods, which usually represent the protein portion of the plate. (Of course, you can also eat exclusively plant-based if you’d like.) Healthy animal-based options include Greek yogurt, cottage cheese, eggs, seafood, poultry and grass-fed beef. Here’s an example of the types of meals you’d eat 80% of the time.

80/20 rule: Here’s how to approach 20% of your diet

Since you’re fueling your body with the nutrition it needs most of the time, the rest of the time is the eater’s choice. That means you can have some ice cream after dinner one day and a slice of pizza for lunch the next day. This approach can be helpful because when less healthful foods are deemed off-limits, you may be more likely to overeat them.

Not only that, but it’s stressful to try to avoid your favorite foods. Let’s say you love French fries. Every time you see them in a restaurant, on TV or while scrolling Instagram, your brain must work overtime to consciously avoid them. Eventually, this mental workout becomes too exhausting to maintain, priming you to throw in the towel and just eat the darned fries.

So, with the 80/20 diet, you may be able to avoid mental gymnastics by allowing yourself some fries without deterring from your health goals since you’re eating nutritious foods the majority of the time.

80/20 rule pitfalls: When the 20% mindset goes awry

Since there aren’t any official rules, people structure the 80/20 plan differently, and certain approaches may be unhelpful. For instance, some people choose to eat a little dessert each night, others prefer a fast-food meal here and there, and some stick with healthy foods during the week and less healthy ones over the weekend. As a registered dietitian, I’d caution against the last approach.

Taking the weekends off plays into the on/off mentality — that you’re ‘good’ during the week and ‘bad’ on weekends. This can backfire in a couple of ways. First, you may be unnecessarily limiting your food choices — and therefore, your enjoyment — during the week. Being satisfied with your food choices helps you sustain them, and that means you’ll maintain the benefits they provide. Think: Better energy during the day and sleep at night, improvements in mental well-being, healthier digestion, and a lower risk of numerous illnesses. You’ll also avoid the sluggishness and other unpleasant feelings that accompany a full day (or two) of less healthful eating.

Next, going ‘off’ plan on the weekend is comparable to a cheat day mentality. The word ‘cheat’ implies that you’re behaving in an inappropriate way, which can affect your mental health. The truth is, your health isn’t just about what you’re eating; it’s also about how you frame your inner conversations about food (in addition to other factors, like getting adequate sleep and exercise). So, when you use words like ‘cheat’ or ‘bad,’ you’re talking to yourself in a way that could promote guilt and shame around food, resulting in an unhealthy relationship with food.

Benefits of the 80/20 rule diet

Indeed, the emphasis on eating well most of the time is in line with what registered dietitians and other qualified health professionals recommend. Nothing is off limits, so you can eat the less healthy foods you love within reason — up to 20% of the time. Plus, there’s no tracking or counting of any kind, and these habits, while helpful, can also be triggering or overwhelming to some people. Finally, the 80/20 diet can be adapted to whatever eating pattern you prefer, be it gluten free, vegan, low FODMAP, or anything else.

Downsides of the 80/20 diet

The flexibility of the diet is both a pro and a con. Without much structure or guidance, you’re in the decision-making driver’s seat about what to eat. Add to that the fact that you’re not just making food decisions during the day; you may also be making work, school or family decisions, and the reality is that all of this drains your mental energy. This is known as decision fatigue, and research suggests it can result in less self-control.

Here’s how this can play out: You hit a decision-making wall and don’t want to think about what to make for dinner, how to balance your plate, or whether you’ve gone above the 20% window. So, to make things easier for yourself, you log into Uber Eats and choose what looks good, which may be a less healthy choice. Since 20% of your diet can come from less healthy foods, this may be appropriate, but if you do it too often or if it makes you feel out of control and guilty afterward, it can interfere with your physical or mental health. And as stated earlier, if you’re thinking of the 20% relaxed eating period as a cheat meal or day, it can also deter from your mental well-being.

Also, the 80/20 plan doesn’t address why you may make less healthy choices. For instance, if you eat when you’re stressed or bored, the plan won’t teach you how to cope with these emotions. Additionally, the 80/20 diet doesn’t offer information about other supportive tools, such as learning to detect when you’re hungry, but not ravenous, and when you’re comfortable, but not stuffed.

Bottom line

The reality is that good health involves a series of behaviors — including exercise, stress management and sleep hygiene — that go beyond your eating habits. But nutritious eating is a strong foundation, and if the 80/20 diet helps you eat better without creating stress or guilt, you’ll benefit from the plan.