Trying to follow the research about good nutrition can be more frustrating than helpful. When your Google search on "avocados" offers contradicting headlines, it's confusing.

Why isn't science able to tell us what foods are good for us? The truth is that food science is much less black-and-white than we want it to be. The best defense is to eat a balanced diet, stay informed, and read up — even if that last step gives you contradictory advice.

There’s a disconnect between science and the way we present that science. While scientific studies may imply a certain outcome, the real answer is not so clear-cut.

We frequently take these correlations in research and assume causation. In other words, if an article says people are less likely to have heart disease if they drink red wine, it means that scientists found a pattern that showed fewer instances of heart disease in groups of people who commonly drink red wine. While this is a promising statistic for red wine, this trend could have to do with other factors as well, like people who drink red wine exercise more or are less stressed. It doesn't mean that drinking red wine is necessarily "healthy" or that drinking red wine will prevent heart disease 100 percent of the time.

A one-sided article describing only the reasons why a food is bad for you is never the full story either. The truth is that there are numerous scientific studies that provide different evidence, which we can use to build a more comprehensive understanding of each food. That’s how we’ve approached the list below.

Above all, remember that moderation and balance are the keys. A food that’s good for you in some ways may be less good for you in others.

1. Avocados

close up avocadoAvocados can improve heart health by lowering bad cholesterol. (Photo: threelayercake [CC BY-ND 2.0]/Flickr)

The good: Avocados contain healthy monounsaturated fats and are packed with more than 20 vitamins. They can also improve heart health by lowering bad cholesterol. And they’re great for your vision too, because they have natural chemicals that reduce eye damage.

The bad: Avocados have a high calorie content, which means if weight loss is your main focus, too many avocados won’t help you.

2. Pickles

pile of picklesFermented foods, such as pickles can be good for intestinal health. (Photo: swong95765 [CC BY 2.0]/Flickr)

The good: Pickles can be good for intestinal health because they are a fermented food. They are good for your digestive health because they contain live (meaning good) bacteria, which help to regulate the immune system. They can also offer antioxidant protection because pickling fruits and veggies preserves their natural antioxidants.

The bad: Moderation when eating pickles may be a wise decision. The average pickle, while low in calories, contains about 313 mg or 19 percent of your suggested daily intake of sodium.

3. Coffee

coffee with heartDespite its high caffeine content, coffee also has some health benefits. (Photo: Divya Thakur [CC BY-SA 2.0]/flickr)

The good: Despite its bad rep, coffee has demonstrated some health benefits in recent research. Coffee may help fight type 2 diabetes with its ability to regulate blood sugar. Coffee has also demonstrated an inverse relationship with the risk of many different cancers.

The bad: Coffee contains caffeine, and caffeine can cause negative health effects such as insomnia, anxiety, restlessness, rapid heartbeat and more.

4. Chocolate

close-up chocolateChocolate could lower your risk of heart disease and stroke. (Photo: Lee McCoy [CC BY-ND 2.0]/Flickr)

The good: Chocolate could be good for your heart and your brain. It has been linked to lowered risks of both heart disease and stroke. An NYU study found that people who ate 100 grams of cocoa powder scored higher on memory tests.

The bad: Here’s the catch: While 100 grams of cocoa powder could possibly improve memory (which is a good excuse for a little dessert!), chocolate isn’t going to help the rest of your body, especially when it comes to your daily calorie intake.

5. Red wine

red wine staticWhile too much alcohol isn't good for you, red wine can increase good cholesterol. (Photo: Angelo Amboldi [CC BY-ND 2.0]/Flickr)

The good: Red wine, in moderation, might reduce risk of heart disease by increasing good cholesterol in your body. It has also demonstrated the ability to burn fat, although the same is also true of red grape juice, at least in this experiment.

The bad: More is less when it comes to red wine. While one or two glasses a day might result in health benefits, drinking more than that has been shown to lead to abnormal heart rhythms, high blood pressure, liver problems and more. And of course, red wine is high in calories, so it can increase weight gain.

6. Nuts

nutsDespite high fat content, nuts are filled with nutrients. (Photo: Mariya Chorna [CC BY 2.0]/Flickr)

The good: Consuming nuts each day is good for your heart because nuts are packed with nutrients and can lower bad cholesterol levels in your blood, which is the main cause of heart disease.

The bad: The negatives of nuts include a high fat and calorie content, which can lead to weight gain.

7. Eggs

eggs in cartonThe egg yolk is packed with vitamins and nutrients. (Photo: Amy Ross [CC BY-ND 2.0]/Flickr)

The good: Egg yolks are absolutely bursting with different nutrients and vitamins. From one egg yolk, your body will benefit from calcium, iron, phosphorus, zinc, thiamin, folate and panthenic acid, B6 and B12.

The bad: Eggs are high in cholesterol. About 300 milligrams of sodium is what’s recommended daily by the American Heart Association, and eating one egg comes in at 185 mg, more than half of that recommendation.

8. Red meat

red meat and knifeEating red meat in moderation can increase protein levels in the body. (Photo: Ronald Sarayudej [CC BY 2.0]/Flickr)

The good: Studies have shown those who eat more lean beef have higher levels of protein, zinc, potassium and B vitamins. It's important to choose lean beef that hasn’t been processed.

The bad: Red meat has been linked to an increased risk of cancer. People who eat 3 ounces of red meat per day are 13 percent more likely to die from heart disease or cancer, according to a study published in International Journal of Epidemiology. This doesn’t mean red meat will kill you, but it does mean it could be unhealthy to eat too much of it. Eating red meat can also harden blood vessels as well as increase your risk of type 2 diabetes.

9. Beer

beerTwo beers per day could potentially lower the risk of heart disease. (Photo: Martin Garrido [CC BY 2.0]/Flickr)

The good: Drinking an IPA may not be a bad idea now that we suspect the hops in beer act as inflammation fighters and can improve digestion. In addition to this, the high silicon-content of beer helps to promote strong bones. In various studies, scientists have found that those who drink about two beers per day are at a 25 percent lower risk of getting heart disease.

The bad: As we all know, beer isn’t the first thing you’d want to grab when you’re on a diet. It’s high in calories and can foster weight gain. It’s also important to remember that alcohol is addictive and can lead to liver disease if it’s over-consumed.

When it comes to the truth about the health of foods, science can give us answers about the health effects or benefits linked to certain foods, but it’s up to us to remember that almost anything is better in moderation and in partnership with an all-around healthy lifestyle.

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