Not all calories are created equal.

Different foods go through different metabolic pathways in your body.

They can have vastly different effects on your hunger, hormones and the number of calories you burn.

Here are the 20 most weight-loss-friendly foods on earth that are supported by science.

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Once feared for being high in cholesterol, whole eggs have been making a comeback.

New studies show that they neither adversely affect blood cholesterol nor cause heart attacks (1, 2).

What's more, they’re one of the best foods to eat if you need to lose weight, as they’re high in protein, healthy fats and can make you feel full with a very low amount of calories.

One study in 30 overweight women showed that eating eggs for breakfast, instead of bagels, increased feelings of fullness (satiety) and made participants eat less for the next 36 hours (3).

Another eight-week study found that eggs for breakfast increased weight loss on a calorie restricted diet, compared to bagels (4).

Eggs are also incredibly nutrient dense and can help you get all the nutrients you need on a calorie-restricted diet. Interestingly, almost all the nutrients are found in the yolks.

Summary Eggs are very filling and nutrient-dense. Compared to refined carbs like bagels, eggs can suppress appetite later in the day and may even promote weight loss.

Leafy greens include kale, spinach, collards, swiss chards and a few others.

They have several properties that make them perfect for a weight loss diet, such as being low in calories and carbohydrates and loaded with fiber.

Eating leafy greens is a great way to increase the volume of your meals, without increasing the calories. Numerous studies show that meals and diets with a low energy density make people eat fewer calories overall (5).

Leafy greens are also incredibly nutritious and very high in many vitamins, antioxidants and minerals, including calcium, which has been shown to aid fat burning in some studies (6).

Summary Leafy greens are an excellent addition to your weight loss diet. Not only are they low in calories but also high in fiber that helps keep you feeling full.

Fatty fish like salmon is incredibly healthy and very satisfying, keeping you full for many hours with relatively few calories.

Salmon is loaded with high-quality protein, healthy fats and various important nutrients.

Fish — and seafood in general — may also supply a significant amount of iodine.

This nutrient is necessary for proper thyroid function, which is important to keep your metabolism running optimally (7).

Studies show that a significant number of people don’t fill their iodine needs (8).

Salmon is also loaded with omega-3 fatty acids, which have been shown to help reduce inflammation, which is known to play a major role in obesity and metabolic disease (9, 10).

Mackerel, trout, sardines, herring and other types of fatty fish are also excellent.

Summary Salmon is high in both protein and omega-3 fatty acids, making it a good choice for a healthy weight loss diet.

Cruciferous vegetables include broccoli, cauliflower, cabbage and Brussels sprouts.

Like other vegetables, they’re high in fiber and tend to be incredibly filling.

What's more, these types of veggies generally contain decent amounts of protein.

They're not nearly as high in protein as animal foods or legumes but still high compared to most vegetables.

A combination of protein, fiber and low energy density makes cruciferous vegetables the perfect foods to include in your meals if you need to lose weight.

They’re also highly nutritious and contain cancer-fighting substances (11).

Summary Cruciferous vegetables are low in calories but high in fiber and nutrients. Adding them to your diet is not only an excellent weight loss strategy but may also improve your overall health.

Meat has been unfairly demonized.

It has been blamed for various health problems despite a lack of good evidence to back up these negative claims.

Though processed meat is unhealthy, studies show that unprocessed red meat does not raise the risk of heart disease or diabetes (12, 13).

According to two big review studies, red meat has only a very weak correlation with cancer in men and no correlation at all in women (14, 15).

The truth is, meat is a weight-loss-friendly food because it's high in protein.

Protein is by far the most filling nutrient, and eating a high-protein diet can make you burn up to 80–100 more calories per day (16, 17, 18).

Studies have shown that increasing your protein intake to 25–% of daily calories can cut cravings by 60%, reduce your desire for late-night snacking by half and cause weight loss of almost one pound (0.45 kg) per week (19, 20).

If you're on a low-carb diet, feel free to eat fatty meats. However, if you're on a moderate- to high-carbohydrate diet, choosing lean meats may be more appropriate.

Summary Eating unprocessed lean meat is an excellent way to increase your protein intake. Replacing some of the carbs or fat in your diet with protein could make it easier for you to lose excess fat.

White potatoes seem to have fallen out of favor for some reason.

However, they have several properties that make them a perfect food — both for weight loss and optimal health.

They contain an incredibly diverse range of nutrients — a little bit of almost everything you need.

There have even been accounts of people living on nothing but potatoes alone for extended periods of time.

They’re particularly high in potassium, a nutrient that most people don't get enough of and that plays an important role in blood pressure control.

On a scale called the Satiety Index, which measures how filling different foods are, white, boiled potatoes scored the highest of all the foods tested (21).

What this means is that by eating white, boiled potatoes, you will naturally feel full and eat less of other foods.

If you allow potatoes to cool for a while after boiling, they will form high amounts of resistant starch, a fiber-like substance that has been shown to have various health benefits, including weight loss (22).

Sweet potatoes, turnips and other root vegetables are also excellent.

Summary Boiled potatoes are among the most filling foods. They’re particularly good at reducing your appetite, potentially suppressing your food intake later in the day.

Tuna is another low-calorie, high-protein food.

It’s lean fish, meaning it’s low in fat.

Tuna is popular among bodybuilders and fitness models who’re on a cut, as it's a great way to increase protein intake while keeping total calories and fat low.

If you're trying to emphasize protein intake, make sure to choose tuna canned in water, not oil.

Summary Tuna is an excellent, lean source of high-quality protein. Replacing other macronutrients, such as carbs or fat, with protein is an effective weight loss strategy on a calorie-restricted diet.

Some beans and other legumes can be beneficial for weight loss.

This includes lentils, black beans, kidney beans and some others.

These foods tend to be high in protein and fiber, which are two nutrients that have been shown to lead to satiety.

They also tend to contain some resistant starch.

The main problem is that a lot of people have difficulties tolerating legumes. For this reason, it’s important to prepare them properly.

Summary Beans and legumes are a good addition to your weight loss diet. They’re both high in protein and fiber, contributing to feelings of fullness and a lower calorie intake.

As mentioned above, meals and diets with a low energy density tend to make people eat fewer calories.

Most foods with a low energy density are those that contain lots of water, such as vegetables and fruits.

But you can also just add water to your food, making a soup.

Some studies have shown that eating the exact same food turned into a soup rather than as solid food, makes people feel more satiated and eat significantly fewer calories (23, 24).

Just make sure not to add too much fat to your soup, such as cream or coconut milk, as this can significantly increase its calorie content.

Summary Soups can be an effective part of a weight loss diet. Their high water content makes them very filling. However, try to avoid creamy or oily soups.

Dairy products tend to be high in protein.

One of the best ones is cottage cheese, which — calorie for calorie — is mostly protein with very few carbs and little fat.

Eating cottage cheese is a great way to boost your protein intake. It’s also very satiating, making you feel full with a relatively low number of calories.

Dairy products are also high in calcium, which may aid fat burning (25).

Other low-fat, high-protein dairy products include Greek yogurt and skyr.

Summary Eating lean dairy products, such as cottage cheese, is one of the best ways to get more protein without significantly increasing your calorie intake.

Avocados are a unique fruit.

While most fruits are high in carbs, avocados are loaded with healthy fats.

They’re particularly high in monounsaturated oleic acid, the same type of fat found in olive oil.

Despite being mostly fat, avocados also contain a lot of water and fiber, making them less energy-dense than you may think.

What’s more, they’re a perfect addition to vegetable salads, as studies show that their fat content can increase carotenoid antioxidant absorption from the vegetables 2.6- to 15-fold (25).

They also contain many important nutrients, including fiber and potassium.

Summary Avocados are a good example of a healthy fat source you can include in your diet while trying to lose weight. Just make sure to keep your intake moderate.

Apple cider vinegar is incredibly popular in the natural health community.

It’s often used in condiments like dressings or vinaigrettes, and some people even dilute it in water and drink it.

Several human-based studies suggest that apple cider vinegar can be useful for weight loss.

Taking vinegar at the same time as a high-carb meal can increase feelings of fullness and make people eat 200–275 fewer calories for the rest of the day (26, 27).

One 12-week study in obese individuals also showed that 15 or 30 ml of vinegar per day caused weight loss of 2.6–3.7 pounds, or 1.2–1.7 kilograms (28).

Vinegar has also been shown to reduce blood sugar spikes after meals, which may have various beneficial health effects in the long term (29, 30).

Summary Adding apple cider vinegar to your vegetable salad may help curb your appetite, potentially leading to greater weight loss.

Despite being high in fat, nuts are not as fattening as you would expect.

They're an excellent snack, containing balanced amounts of protein, fiber and healthy fats.

Studies have shown that eating nuts can improve metabolic health and even promote weight loss (31, 32).

What’s more, population studies have shown that people who eat nuts tend to be healthier and leaner than those who don't (33).

Just make sure not to go overboard, as they’re still fairly high in calories. If you tend to binge and eat massive amounts of nuts, it may be best to avoid them.

Summary Nuts can make a healthy addition to an effective weight loss diet when consumed in moderation.

Though cereal grains have received a bad reputation in recent years, some types are definitely healthy.

This includes some whole grains that are loaded with fiber and contain a decent amount of protein.

Notable examples include oats, brown rice and quinoa.

Oats are loaded with beta-glucans, soluble fibers that have been shown to increase satiety and improve metabolic health (34, 35).

Both brown and white rice can contain significant amounts of resistant starch, particularly if cooked and then allowed to cool afterward (36).

Keep in mind that refined grains are not a healthy choice, and sometimes foods that have "whole grains" on the label are highly processed junk foods that are both harmful and fattening.

If you're on a very low-carb diet, you'll want to avoid grains, as they’re high in carbs.

But there's otherwise nothing wrong with eating whole grains if you can tolerate them.

Summary You should avoid refined grains if you’re trying to lose weight. Choose whole grains instead — they’re much higher in fiber and other nutrients.

Eating chili peppers may be useful on a weight loss diet.

They contain capsaicin, a substance which has been shown to reduce appetite and increase fat burning in some studies (37, 38, 39).

This substance is even sold in supplement form and a common ingredient in many commercial weight loss supplements.

One study showed that eating 1 gram of red chili pepper reduced appetite and increased fat burning in people who didn't regularly eat peppers (40).

However, there was no effect in people who were accustomed to eating spicy food, indicating that a certain level of tolerance can build up (40).

Summary Eating spicy foods that contain chili peppers may reduce your appetite temporarily and even increase fat burning. However, tolerance seems to build up in those who eat chili regularly.

Most health experts agree that fruit is healthy.

Numerous population studies have shown that people who eat the most fruit (and vegetables) tend to be healthier than people who don't (41, 42).

Of course, correlation does not equal causation, so these studies don't prove anything. However, fruits do have properties that make them weight-loss-friendly.

Even though they contain natural sugar, they have a low energy density and take a while to chew. Plus, their fiber content helps prevent sugar from being released too quickly into your bloodstream.

The only people who may want to avoid or minimize fruit are those on a very low-carb, ketogenic diet or have an intolerance.

For most fruits can be an effective and delicious addition to a weight loss diet.

Summary Though fruits contain some sugar, you can easily include them on a weight loss diet. They’re high in fiber, antioxidants and various nutrients that slow the rise of blood sugar after meals.

One fruit that deserves to be highlighted is grapefruit. Its effects on weight control have been studied directly.

In a 12-week study in 91 obese individuals, eating half a fresh grapefruit before meals led to weight loss of 3.5 pounds (1.6 kg) (43).

The grapefruit group also had reduced insulin resistance, a metabolic abnormality that is implicated in various chronic diseases.

Therefore, eating half a grapefruit about half an hour before some of your daily meals may help you feel more satiated and eat fewer overall calories.

Summary Studies indicate that grapefruit may suppress appetite and reduce calorie intake when eaten before meals. It’s worth a try if you’re want to lose weight.

Chia seeds are among the most nutritious foods on the planet.

They contain 12 grams of carbohydrates per ounce (28 grams), which is pretty high, but 11 of these grams are fiber.

This makes chia seeds a low-carb-friendly food and one of the best sources of fiber in the world (44).

Because of its high fiber content, chia seeds can absorb up to 11–12 times their weight in water, turning gel-like and expanding in your stomach (45).

Though some studies have shown that chia seeds can help reduce appetite, they did not find a statistically significant effect on weight loss (46, 47).

However, given their nutrient composition, it makes sense that chia seeds could be a useful part of your weight loss diet.

Summary Chia seeds are very high in fiber, which fills you up and reduces appetite. For this reason, they can be useful on a weight loss diet.

Not all fats are created equal.

Coconut oil is high in fatty acids of a medium length, called medium-chain triglycerides (MCTs).

These fatty acids have been shown to boost satiety better than other fats and increase the number of calories burned (48, 49).

What’s more, two studies — one in women and the other in men — showed that coconut oil reduced amounts of belly fat (50, 51).

Of course, coconut oil still contains calories, so adding it on top of what you're already eating is a bad idea.

It’s not about adding coconut oil to your diet but about replacing some of your other cooking fats with coconut oil.

However, studies show that coconut oil is less satiating than MCT oil — a supplement that contains much higher numbers of medium-chain triglycerides (52).

Extra virgin olive oil is worth mentioning here, as it’s probably one of the healthiest fats on the planet.

Summary Coconut oil contains medium-chain triglycerides (MCTs) that may increase satiety after meals. MCT oil supplements are even more effective.

Yogurt is another excellent dairy food.

Certain types of yogurt contain probiotic bacteria that can improve the function of your gut.

Having a healthy gut may help protect against inflammation and leptin resistance, which is one of the main hormonal drivers of obesity.

Make sure to choose yogurt with live, active cultures, as other types of yogurt contain virtually no probiotics.

Also, consider choosing full-fat yogurt. Studies show that full-fat dairy — but not low-fat — is associated with a reduced risk of obesity and type 2 diabetes over time (53).

Low-fat yogurt is usually loaded with sugar, so it’s best to avoid it.

Summary Probiotic yogurt can increase your digestive health. Consider adding it to your weight loss diet but make sure to avoid products that contain added sugar.

It’s easy to find healthy foods to include on a weight loss diet.

These are mainly whole foods like fish, lean meat, vegetables, fruit, nuts, seeds and legumes.

Several processed foods, such as probiotic yogurt, extra-virgin olive oil and oatmeal are also excellent choices.

Along with moderation and regular exercise, eating these nutritious foods should pave your way to success and a healthier life.