When trying to lose weight quickly, some people turn to fad diets that promise fast results using questionable methods.

These plans are typically very low in calories, restrict many healthy foods, and involve following strict rules, like eating only one food.

Even though any type of low calorie diet can result in rapid weight loss, there are major concerns with fad diets that promote the use of unnecessary — and even dangerous — rules.

The pineapple diet is a fad diet that people have used since the 1970s to shed excess body fat.

In this article, I explain what the pineapple diet is and why it’s not a safe way to lose weight.

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The pineapple diet, also known as the “Sexy Pineapple Diet,” was created by a Danish psychologist named Sten Hegeler.

Hegeler and his wife, Inge, published the book “The Sexy Pineapple Diet” in 1970. The diet promised to help people slim down and improve other aspects of health, like sexual vitality.

The diet consists of eating nothing but pineapple for two days out of the week, then eating normally for five days.

According to some sources, the plan allows you to consume other foods during the 2 pineapple-only days, so long as the food provides fewer than 500 total calories (1).

Keep in mind that the full book is not available to view online, and there’s not a lot of information available regarding foods to eat, rules, length of the diet, and other recommendations.

According to an interview with Hegeler, the diet wasn’t based on any scientific evidence. The author simply liked pineapple, so he thought that creating a diet based on consuming large amounts of pineapple was a good idea (1).

Online sources claim that most people who follow this diet do so for 2–7 days, but some people follow the diet for several weeks until they reach their “goal” weight.

In addition to the original Sexy Pineapple Diet, there are other pineapple-based diets and “cleanses” promoted online that involve eating nothing but pineapple for 2–7 days.


The Sexy Pineapple Diet is a diet plan that recommends consuming nothing but pineapple for 2 days a week. Other versions of the pineapple diet exist, each with its own rules.

When following the Sexy Pineapple Diet, you’ll eat nothing but pineapple for two days per week. It’s not clear whether the days have to be consecutive.

On the other five days, you’ll eat normally. Again, specific recommendations from the book are not available, so it’s not clear what type of diet Hegeler recommended on the five non-pineapple days.

According to some sources, you’re allowed to eat other foods during the two pineapple days, but it’s not clear which foods are allowed.

Some sources shared that if you’re allergic to pineapple, the book suggests eating fruits like apples, pears, or bananas instead.

Other pineapple-based plans online recommend consuming foods like oats, yogurt, and lean proteins, plus a lot of pineapple.

Some strict versions of the pineapple diet involve eating nothing but pineapple for 2–7 days. These diets do not allow any other foods besides pineapple.

As you can see, there are many types of pineapple-based diets and “cleanses” promoted online, each with their own rules and recommendations.


Depending on the type of pineapple diet, the plan may involve eating nothing but pineapple for 2 to 7 days or eating a lot of pineapple combined with other low calorie foods like oatmeal and lean protein sources.

The Sexy Pineapple Diet recommends eating nothing but pineapple for two days a week. However, some sources say that it allows for other low calorie foods as well, though it’s unclear which foods are recommended.

During the other five days of the week, a person following the Sexy Pineapple Diet follows their normal diet.

Other pineapple-based fad diets recommend eating nothing but pineapple for two to seven days.

This means that you can’t consume any other foods besides pineapple.

If you decide to follow one of these super strict, pineapple-only plans, you’ll be eating pineapple for breakfast, lunch, and dinner.

Healthy whole foods like eggs, vegetables, nuts, seeds, fish, and grains will be off-limits.


Depending on the type of pineapple diet you follow, you may only be allowed to eat pineapple for 2–7 days or to alternate days of only pineapple with days of normal eating.

Eating nothing but pineapple for two to seven days is absolutely unnecessary for weight loss.

Of course, limiting your calorie intake using any method, including unhealthy ones, will promote weight loss.

For example, if you’re used to consuming 2,000 calories per day and then follow a 5-day plan that involves eating nothing but pineapple, you’ll be taking in significantly fewer calories, which will create a calorie deficit.

One cup (165 grams) of cubed pineapple provides just 82.5 calories. Let’s say you consume 6 cups (990 grams) of pineapple per day — 2 cups (330 grams) at each meal. This equates to only 495 calories, which is extremely low (2).

When you’re eating normally, a single meal may contain 500 calories or more, depending on your energy needs.

Any diet that significantly cuts calories and creates an extreme calorie deficit will induce weight loss (3).

However, this doesn’t mean that losing weight using such restrictive methods is safe or effective for long-term weight maintenance.

Also, if you follow a diet plan that significantly cuts calories, you will almost certainly gain back any weight you lose as soon as you return to your normal dietary pattern (4).

Journalists who tried the Sexy Pineapple Diet and documented the experience have lost between 0–2.2 pounds (1 kg) in a week.

However, you can achieve sustainable weight loss using methods that are actually based on scientific research and don’t involve eating just one food for a prolonged period of time.

Lastly, there’s no evidence that the Sexy Pineapple Diet — or any other pineapple-based fad diet, for that matter — is safe or effective for weight loss.

Heleger, the diet’s creator, even admitted that the diet is not based on any sound medical advice. He designed the plan simply because he enjoyed eating pineapple.


Any diet that significantly cuts calories will create a calorie deficit and promote weight loss. However, this isn’t a safe or sustainable way to lose weight. You’ll likely regain the weight once you return to normal eating habits.

It’s unlikely that following the Sexy Pineapple Diet will result in any significant side effects if you follow it for a week. This is because the plan only restricts calories and foods on two days out of the week.

Studies show that diets that significantly restrict calories for 2 days per week, like the 5:2 method of intermittent fasting, can be safe (5).

But chances are you’ll be extremely hungry, irritable, and tired on a fad diet like this one. Journalists who tried the Sexy Pineapple Diet reported these feelings when they documented their experiences.

Because pineapple is so acidic, it might bother your stomach, especially if that’s all you’re eating for an entire day. You may feel nauseated or experience diarrhea.

If you’re following a plan that involves eating nothing but pineapple for 5 days or longer, you could experience side effects like dizziness, passing out, headaches, hunger pains, insomnia, weakness, and extreme hunger (6).

Because pineapple contains less than one gram of protein and fat per cup (165 grams) and lacks many vitamins and minerals, like vitamin B-12 and vitamin E, your body won’t be getting the nutrients it needs to function optimally (2).

Plus, many people consider protein to be the most filling macronutrient, so when you’re not eating adequate amounts of protein, you won’t feel full (7).

Because pineapple is lacking in many important nutrients, following a plan that involves eating nothing but pineapple for longer than a few days can also put you at risk for developing a nutrient deficiency.

Also, it’s never a good idea to engage in such restrictive eating habits. It could lead to long-term complications involving your relationship with your body and food, including eating disorders.

For example, you may be afraid to resume normal eating habits after finishing a restrictive diet like the Sexy Pineapple Diet because you fear regaining the weight you lost.

Heads up

Trying to “do it right” when it comes to nutrition may feel tempting, but it can backfire.

If you are preoccupied with food or your weight, feel guilt surrounding your food choices, or routinely engage in restrictive diets, consider reaching out for support. These behaviors may indicate a disordered relationship with food or an eating disorder.

Disordered eating and eating disorders can affect anyone, regardless of gender identity, race, age, body size, socioeconomic status, or other identities.

They can be caused by any combination of biological, social, cultural, and environmental factors — not just by exposure to diet culture.

Feel empowered to talk with a qualified healthcare professional, such as a registered dietitian, if you’re struggling.

You can also chat, call, or text anonymously with trained volunteers at the National Eating Disorders Association helpline for free or explore the organization’s free and low cost resources.

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Pineapple-based weight loss plans can result in side effects like extreme hunger, nausea, headaches, and other unpleasant side effects. Following a pineapple-only diet long-term can be dangerous and put you at risk of developing nutrient deficiencies.

You do not need to follow any restrictive diet to lose weight. It’s not a good idea to follow any diet or cleanse that recommends drastically cutting calories, only eating one food, or cutting out entire food groups.

Even though you may be tempted to try a diet that promises rapid weight loss, you can lose body fat by following safe, evidence-based plans that involve making long-term dietary and lifestyle changes that leave you feeling deprived.

If you want to lose weight, it’s best to create a small calorie deficit by cutting out or reducing your intake of sugary beverages, ultra-processed foods like fast food, and fried foods.

At the same time, make an effort to eat more nutrient-dense foods, like vegetables and fruits.

Adding more protein and fiber into your diet is also a helpful way to induce weight loss and maintain a healthy body weight, as foods rich in these nutrients help you feel full and keep you satisfied between meals (8, 9, 10).

Additionally, becoming more active by engaging in regular physical activity can be helpful for promoting weight loss and can also improve other aspects of health, like cardiorespiratory fitness (11).

Weight loss isn’t always easy and can take time. If you’re unsure of where to start on your weight loss journey, consider working with a registered dietitian.

They can help you create a dietary pattern that works best for your needs and that you can follow for life.


You do not need to follow any restrictive diet to lose weight. It’s not a good idea to follow any diet or cleanse that recommends drastically cutting calories, only eating one food, or cutting out entire food groups.

Like other fad diets, pineapple-based weight loss plans — including the Sexy Pineapple Diet — are not healthy ways to lose weight.

They involve significantly restricting calories and eating only pineapple for 2–7 days.

Not only are these methods unnecessary for weight loss, but they can result in unpleasant and even dangerous side effects.

When you’re trying to lose weight, it’s best to avoid pineapple-based weight loss diets and other restrictive fad diets and instead focus on making healthy dietary and lifestyle modifications that can help promote weight loss in a safe way.

Just one thing

Try this today: If you’re trying to lose weight, it’s best to avoid drastic measures like following a very low calorie fad diet.

Consider making an appointment with trusted healthcare professional, like a registered dietitian, if you want to lose weight. They can help you develop a plan using healthy and non-restrictive methods that you feel good about following and that you can maintain for life.

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