We took a scientific look at whether non-fat or full-fat foods are worse for you - here's the verdict
- Fat can play a key role in a balanced diet: it keeps people full and energized and helps their bodies absorb more vitamins and minerals.
- Some recent research suggests that eating dairy fats may help stave off obesity.
- But certain fats (especially trans fat) should be avoided.
- Moderation is key - nutrition experts say focusing too much on specific nutrients misses the main point of healthy eating.
Fat has taken turns as both a villain and a hero for healthy eaters.
In the 1990s, the US Department of Agriculture put fats and oils with sweets at the top of its food pyramid, suggesting Americans should generally avoid them. But more recent research revealed that telling Americans not to consume fat, while paying less attention to their intake of sugar and processed carbohydrates, steered waistlines in the wrong direction.
Fat is a stable source of energy, and, unlike sugar, it won't necessarily make you fat. It keeps people full and helps the body absorb vitamins and minerals. Plus, it helps nerves and cells stay healthy. There's some evidence that certain fats may even keep us from getting fat: recently, full-fat dairy products were found to potentially help prevent obesity.
But fat's recent reputation boost has created some confusion for consumers. Is it alright to put cream in your coffee and fill the fridge with butter and other full-fat products?
Unfortunately, there's no one-fat-fits-all answer to that question, and more conclusive research on dairy is needed. But when you're choosing which foods to buy at the store, here are the important points to know:
Dairy fat isn't inherently good or bad for you
Many nutrition experts agree that focusing on specific fat, calorie, or protein numbers instead of prioritizing whole foods and healthy eating patterns can miss the larger point of nutrition science.
Dairy fat isn't inherently good or bad, but it can serve an important function in a balanced diet. Fatty foods take longer to break down inside your stomach, so products with some natural fat will likely keep you full for longer.
Yale nutrition expert David Katz said that when people ask him whether they should pick low-fat versus non-fat products, he gives a shrug.
"My preferred answer is: Who cares?" Katz told Knowable Magazine last year. "The fat amount doesn't seem to make a difference. What really matters: Are the foods wholesome, are they arranged sensibly, and is there a balance? You can achieve all of that with high- or low-fat intakes."
Registered dietitian Sharon Palmer, author of "The Plant-Powered Diet," told Business Insider that recent scientific findings on the benefits of fat aren't a good reason to throw caution to the wind. Palmer said people should not overindulge in rich dairy treats, especially any with added syrups or sugar.
"Research on dairy fat has gotten people confused, and they think that it's 'better' to eat these indulgent dairy products," Palmer said in an email. "Excess calories lead to weight gain, which leads to health problems. We must keep this in mind."
Still, a 2015 review of 53 studies found that among more than 68,000 dieters, those who tried low-fat diets weren't as good at keeping weight off for periods longer than a year. The researchers warned, however, that their findings did not indicate that adding fat into your diet is the answer to lasting weight maintenance.
"We need to look beyond the ratios of calories from fat, carbs, and protein to a discussion of healthy eating patterns, whole foods, and portion sizes," author Dierdre Tobias said when the meta-study came out.
As is the case with most types of food, not all fats are created equal
Here's what the latest research shows:
- You're probably eating more than enough fat, but it may not be the best kind for your body. A 2016 Pew Research Center study showed that Americans have almost doubled the amount of fat and oil in their diets since the 1970s. In fact, we're eating more of almost every kind of food these days, with the notable exceptions of healthy veggies and eggs.
- Trans fats are hyper-processed oils that should be avoided. Solid-state vegetable oils are laboratory-heated to prevent spoilage (they often show up in nutrition labels as "partially hydrogenated oil"). These types of fats were once commonly used in deep-fryer oils, margarines, and packaged foods from frozen pizzas to cookies. But manufacturers are starting to avoid them, since trans fats raise our bad LDL cholesterol levels while lowering the good kind of HDL cholesterol. Researchers estimated that during the heyday of trans fats in the 1990s, they led to roughly 50,000 preventable deaths every year in the US. The FDA is in the process of rolling out a ban: companies have until June 18, 2018 to stop using trans fats.
- It's good to limit saturated fats from things like red meat, coconut oil, and cheese. Some cardiologists have suggested that saturated fat isn't the artery clogger it was once thought to be, but research suggests most people are still better off nibbling limited doses of these foods.
- There are some very good fats out there. Avocados, nuts, fish, and olive oils all have high levels of monounsaturated fats, which can actively lower your cholesterol. They're also staples of the Mediterranean diet, which is increasingly touted as one of the best for staying healthy.
- "Everything in moderation" is still good advice. According to Palmer: "We must keep in mind that fat is very concentrated. Just one tablespoon of oil provides about 120 calories." Those calories can add up quickly and contribute to weight gain if you're not mindful of portion sizes, she said.
- It's fine to have fat in your diet as long as you don't use it as an excuse to eat sugar. "If you really love a higher-fat yogurt and you have a healthy weight, then I think you can easily fit this in a healthful, balanced diet," Palmer said. "But you might want to keep an eye on sugar levels, which we should be limiting."
Finding a healthy, balanced diet is key
The best fats come from whole, nutrient-rich foods, and are just one part of a sustainable healthy diet. Most researchers agree that the trick to good eating can't be summed up as an eat-this-not-that rule.
Instead, science suggests that your best bet is to eat a variety of fiber-rich veggies, digestion-aiding whole grains, and, yes, some fats.
Cardiologist Aseem Malhotra said in a BMJ podcast last year that adopting a Mediterranean diet that's high in fat and low in refined carbs is part of a 3-pronged health approach that's "more powerful than any drug."
The other two components: a solid daily dose of movement or exercise, and keeping your stress in check.