Low carb? Low fat? What the latest dieting studies tell us
By CANDICE CHOI
AP Food & Health Writer
Wednesday, January 2
NEW YORK (AP) — Bacon and black coffee for breakfast, or oatmeal and bananas?
If you’re planning to try to lose weight in 2019, you’re sure to find a fierce debate online and among friends and family about how best to do it. It seems like everyone has an opinion, and new fads emerge every year.
Two major studies last year provided more fuel for a particularly polarizing topic — the role carbs play in making us fat. The studies gave scientists some clues, but, like other nutrition studies, they can’t say which diet — if any — is best for everyone.
That’s not going to satisfy people who want black-and-white answers, but nutrition research is extremely difficult and even the most respected studies come with big caveats. People are so different that it’s all but impossible to conduct studies that show what really works over long periods of time.
Before embarking on a weight loss plan for the new year, here’s a look at some of what was learned last year.
FEWER CARBS, FEWER POUNDS?
It’s no longer called the Atkins Diet, but the low-carb school of dieting has been enjoying a comeback. The idea is that the refined carbohydrates in foods like white bread are quickly converted into sugar in our bodies, leading to energy swings and hunger.
By cutting carbs, the claim is that weight loss will be easier because your body will instead burn fat for fuel while feeling less hungry. A recent study seems to offer more support for low-carb proponents. But, like many studies, it tried to understand just one sliver of how the body works.
The study, co-led by an author of books promoting low-carb diets, looked at whether varying carb levels might affect how the body uses energy. Among 164 participants, it found those on low-carb diets burned more total calories than those on high-carb diets.
The study did not say people lost more weight on a low-carb diet — and didn’t try to measure that. Meals and snacks were tightly controlled and continually adjusted so everyone’s weights stayed stable.
David Ludwig, a lead author of the paper and researcher at Boston Children’s Hospital, said it suggests limiting carbs could make it easier for people to keep weight off once they’ve lost it. He said the approach might work best for those with diabetes or pre-diabetes.
Ludwig noted the study wasn’t intended to test long-term health effects or real-world scenarios where people make their own food. The findings also need to be replicated to be validated, he said.
Caroline Apovian of Boston University’s School of Medicine said the findings are interesting fodder for the scientific community, but that they shouldn’t be taken as advice for the average person looking to lose weight.
DO I AVOID FAT TO BE SKINNY?
For years people were advised to curb fats, which are found in foods including meat, nuts, eggs, butter and oil. Cutting fat was seen as a way to control weight, since a gram of fat has twice as many calories than the same amount of carbs or protein.
Many say the advice had the opposite effect by inadvertently giving us license to gobble up fat-free cookies, cakes and other foods that were instead full of the refined carbs and sugars now blamed for our wider waistlines.
Nutrition experts gradually moved away from blanket recommendations to limit fats for weight loss. Fats are necessary for absorbing important nutrients and can help us feel full. That doesn’t mean you have to subsist on steak drizzled in butter to be healthy.
Bruce Y. Lee, a professor of international health at Johns Hopkins, said the lessons learned from the anti-fat fad should be applied to the anti-carb fad: don’t oversimplify advice.
“There’s a constant look for an easy way out,” Lee said.
SO WHICH IS BETTER?
Another big study this past year found low-carb diets and low-fat diets were about equally as effective for weight loss. Results varied by individual, but after a year, people in both groups shed an average of 12 to 13 pounds.
The author noted the findings don’t contradict Ludwig’s low-carb study. Instead, they suggest there may be some flexibility in the ways we can lose weight. Participants in both groups were encouraged to focus on minimally processed foods like produce and meat prepared at home. Everyone was advised to limit added sugar and refined flour.
“If you got that foundation right, for many, that would be an enormous change,” said Christopher Gardner of Stanford University and one of the study’s authors.
Limiting processed foods could improve most diets by cutting down overall calories, while still leaving wiggle room for people’s preferences. That’s important, because for a diet to be effective, a person has to be able to stick to it. A breakfast of fruit and oatmeal may be filling for one person, but leave another hungry soon after.
Gardner notes the study had its limitations, too. Participants’ diets weren’t controlled. People were instead instructed on how to achieve eating a low-carb or low-fat in regular meetings with dietitians, which may have provided a support network most dieters don’t have.
SO, WHAT WORKS?
In the short term you can probably lose weight by eating only raw foods, or going vegan, or cutting out gluten, or following another diet plan that catches your eye. But what will work for you over the long term is a different question.
Zhaoping Li, director of clinical nutrition division at the University of California, Los Angeles, says there is no single set of guidelines that help everyone lose weight and keep it off. It’s why diets often fail — they don’t factor into account the many factors that drive us to eat what we do.
To help people lose weight, Li examines her patients’ eating and physical activity routines to identify improvements people will be able to live with.
“What sticks is what matters,” Li said.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
A neuroscientist’s tips for a new year tuneup for your brain
December 28, 2018
Author: Kelly Lambert, Professor of Behavioral Neuroscience, University of Richmond
Disclosure statement: Kelly Lambert does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Partners: University of Richmond provides funding as a member of The Conversation US.
Unlike the effervescent bubbles that stream to the top of champagne flutes on New Year’s Eve, what I call brain bubbles are far from celebratory. These bubbles are metaphorical rather than physical, and they distort the stream of reality processed by our brains. Like a real estate bubble that reflects an inflated perception of home values, a brain bubble twists your perception of the world around you. And when either of these bubbles bursts, the results can be devastating.
Problems arise when distorted information results in flawed decisions that negatively affect our lives. As a neuroscientist who’s worked closely with laboratory rats for over three decades, I’ve gleaned from them a few good strategies people can use to burst brain bubbles and enhance well-being in the year ahead. Rat brains are small but have the same general areas and neurochemicals we have, so these rodents are valuable laboratory models for human behavior.
Getting back down to Earth
Psychoactive drug use, aspects of privilege and poverty, psychiatric illness and, in some cases, religious and political beliefs can all create brain bubbles. Even daily excursions to the virtual world of apps, social media and cybergames sever our connections to concrete aspects of the real world and let distorting brain bubbles develop.
This is especially problematic for children’s brains that are still developing. An ongoing National Institutes of Health study suggests that two hours of screen time each day distorts language and thinking abilities in these junior digital users.
As our attention is hijacked by the closest screen while a Roomba cleans the floor and Alexa orders pizza to be delivered to the front door, what’s left for our brains to do? Sure, we likely face cognitive challenges at work each day, but human brains are built for sophisticated and complex activity – even though we’re often lulled into mindlessly scrolling through a virtual feed. In fact, a brain area often associated with reward and pleasure, the nucleus accumbens, is smaller in people who spend more time checking Facebook posts on their smartphones.
Obviously, some of these distortion-generating circumstances are out of our control. But a heightened awareness of our authentic world can move us toward a more reality-based, well-grounded brain – free of those brain bubbles.
The rats that my students and I train in our studies to physically work for coveted treats (Froot Loops cereal is a favorite) develop healthier emotional responses than the animals we call “trust-fund rats” because they’re merely given their sweet rewards. The harder-working rats have healthier stress hormone levels and engage in more sophisticated search strategies when they encounter a surprise challenge – such as when we move their expected Froot Loop rewards. They’re more persistent as they spend time trying to solve the problem, rather than quickly giving up and walking away.
So whereas one popular New Year’s resolution involves saving up to build financial capital, we can keep our brains in peak condition for the year ahead by building up experiential capital. Real-world experiences represent the best currency for our brain circuits, providing neural security for our future decisions in the coming year. Spending time engaged in hobbies such as knitting or gardening, for example, with complex movements and rich sensory experiences, provides a valuable yield for our brains.
Savor the anticipation
When the calendar flips to a new year, it’s common to reflect on the past and look to the future. According to the neuroscience literature, this anticipation could be one of the most pleasurable – and healthy – tasks our brains engage in all year long.
Dopamine is the poster neurotransmitter for the cognitive endeavor of anticipating. Traditionally known for its role in pleasure, this neurochemical system can be hijacked by psychoactive drugs such as cocaine that serve as potent creators of reality-distorting brain bubbles.
Rodent research provides fascinating insights here, however. Researchers use sophisticated techniques to measure dopamine activity as rats press laboratory levers that reward them with drugs. Surprisingly, this neurochemical system surges when the animal merely anticipates taking the drug as it approaches the drug lever, as well as when the drug is actually infused into the brain.
Anticipating a new start and a new year may be a scaled-down version of approaching the experimental lever for a hit of cocaine – a legal and healthy dopamine dose in this case. You can try to keep this emotional high going through the year by amping up the anticipation in your daily life: Focus more on delayed than immediate gratification. Buying and planning for experiences is more satisfying than material purchases. Mapping out a menu, shopping for ingredients and cooking a meal provides more dopamine time – and brain-engaging behaviors – than nuking a frozen meal and eating it three minutes later.
Seize the reins of your stress
Another way to enhance our well-being through the year is to gain some sense of control over the stress in our lives. Real-time and authentic interactions with the environment can help us gain a sense of control over the inevitable uncertainty and unpredictability we face each day.
I see evidence of this in the lab. When I furnish my rats’ housing with natural elements such as dirt, hollowed-out logs and rocks, they’re busier and less likely to sit around the edge of the cage than animals in boring empty cages. After building their experiential capital, these enriched rats have healthier stress and resilience hormone profiles and engage in bolder behaviors, such as diving to the bottom of swim tanks instead of staying on the top doing their best impression of a dog paddle. As I watch these animals in various tasks, they appear to be gaining control over the challenges they encounter.
Perhaps this is why retired U.S. four-star admiral William McRaven emphasized simple life strategies in his 2014 University of Texas commencement speech, declaring that “if you want to change your life and maybe the world, start off by making your bed.” Then, even if you have a terrible day, you will come home to a made bed, evidence that you had a positive impact in at least one area of your life that day.
And, considering that over 70 percent of the brain’s nerve cells are in the cerebellum, which is involved in movement coordination, any activity that gets us up and moving – whether household chores or hitting the gym – engages the brain in healthy ways.
Starting your brain’s year off right
Lessons from the laboratory rats also provide potential explanations for some of my own personal favorite New Year’s Day traditions – including the mundane tasks of cooking a familiar southern meal, cleaning my closet and watching HGTV’s Dream House giveaway with my family while we all declare what we would do if we won the beautiful house. Move in? Sell it? Make it an Airbnb rental?
Thinking like a neuroscientist, I know that cooking and cleaning are active endeavors with clear outcomes that allow me to gain a small sense of control, decreasing stress hormones. Playfully anticipating winning a new home taps into that feel-good dopamine system as we contemplate more serious options for the new year. And, perhaps the best neurochemical hit of all is the spike in oxytocin, the neurochemical involved in positive social connections, as I spend time with loved ones.
Although it’s common to turn to pharmaceuticals to lift our emotions and improve our mental health, the emotional benefits of many New Year’s traditions remind me that basic responses can serve as what I call “behaviorceuticals” that enhance well-being. New Year’s resolutions may take the form of New Year’s Rx’s as we consider healthy lifestyle choices for the coming year: Shrink those distorting brain bubbles and build realistic connections to enrich life’s simple pleasures.