What Is Bright Line Eating?

Some people looking to lose weight initially have success on a diet but eventually drift off the plan, and the weight piles back on. This yo-yo effect is common and is the reason why many dietitians say that diets don’t work. One person, however, claims to have the solution to this ongoing problem, and it’s led to a diet movement called Bright Line Eating, or BLE.

In her 2017 book, “Bright Line Eating: The Science of Living Happy, Thin and Free,” Susan Peirce Thompson, who holds a PhD in brain and cognitive sciences from the University of Rochester, presents her approach to dieting, which is based on brain science and her own struggles with addiction, her weight and a history of disordered eating. Her theory is rooted in the idea that “the brain blocks weight loss,” she writes. Her solution is to remove that obstruction. U.S. News reached out to BLE for this article, but representatives were unavailable for an interview.

Gaby Vaca-Flores, a registered dietitian and founder of Glow+Greens, a nutrition and skin care consultancy based in Santa Monica, California, says that BLE is designed “to help people break free from food addiction by reframing eating behaviors with four bright lines, aka eating rules.”

These bright lines, Thompson writes, draw “clear, unambiguous boundaries that you just don’t cross, like a nonsmoker just doesn’t smoke.”

“In theory, the bright lines are intended to work together to produce lasting weight loss results,” Vaca-Flores says.
However, these rules might cause more harm than they do good. Cesar Sauza, a registered dietitian and clinical nutrition manager with AltaMed in Los Angeles, says that these strict rules might make the eating plan dangerous.

“Many people already have stress and anxiety when it comes to food, adding rules on top of that is more likely to lead to disordered eating or possibly binge eating further down the line,” says Sauza.

Thompson writes that sugar works on the brain the same way that drugs such as cocaine and heroin do. She points to research highlighting the addictiveness of sweetness to support that notion.

The no-sugar rule is the brightest line of the bunch, and by removing it, you can cure your dependency on food, Thompson argues. This means eliminating all sources of sugar, including:

Thompson says that for some people, flour is an insidiously addictive food. While the “science of flour addiction” isn’t fully understood, she writes that it’s known to elevate blood sugar levels. But the fact that the number one food people crave is typically cited as pizza – with its thick, doughy crust – is a clear indication that there’s something addictive about bread and its constituent parts, she argues.

Though some people avoid wheat flour to remove gluten from their diets, Thompson recommends avoiding all kinds of flour, no matter what plant they come from. If you’re avoiding flour, you’ll need to remove the following items from your diet:

Teaching your body that there are certain times of day, and those times only, when it’s OK to eat is part of the conditions BLE uses to keep folks from overindulging throughout the day.

Thompson also writes that designating a special place to eat, such as the dining room table, rather than mindlessly eating in your car or on the couch in front of the television, can also help you keep your weight loss efforts on track. She says setting these boundaries around when and where you eat can help you overcome the willpower gap.

The final pillar of the Bright Line Eating plan is to carefully control portion sizes. Thompson writes that “the quantities of Bright Line meals are generous, but they are finite.” She encourages dieters to weigh or measure every meal to carefully quantify the portion size. The point of this is to remove another decision, thereby helping to bridge the willpower gap; more on that below.

This restriction, she writes, “gave me psychologic freedom. When I weigh my food, I know I’m getting the right amount. And when I hear that voice in my head telling me that maybe I didn’t get enough food and I should have some more, I know it’s lying to me and I can ignore it.”

The idea across these four tenets is to remove in-the-moment decision-making as much as possible and dial in an automatic reflex toward a healthier way of eating.

While Sauza says that these four rules might be recommendations that he would make to patients, he says “by no means do I make these recommendations all or nothing. For most patients we have to shift these habits gradually if we want them to stick.”

Thompson liberally cites research on social science and brain research studies, as well as her own academic background in cognitive science, to support her theories. She says that many people struggle with the cycle of yo-yo dieting because their brains block their efforts in three key ways. These include:

Willpower, according to Thompson, is housed in the anterior cingulate cortex; like other portions of the brain, this section runs on glucose, or blood sugar, and is highly sensitive to fluctuations in the levels of sugar in the body that it can draw on for energy. As you make decision after decision all day long, which uses up brain power and thus the body’s energy, your blood sugar levels get depleted. In this section of the brain, that means decision-making becomes more challenging.

In terms of dieting, this is when you might say “forget it” and give in to temptation. Learning to overcome that gap between waning willpower and the constant temptations of modern society creates the Thompson-termed willpower gap. Glucose, as well as prayer and meditation, social connection, sleep and gratitude, can help restore your brain’s ability to make healthy decisions, she argues.

Insatiable hunger, or the drive to eat even when you’re already full, is linked to leptin resistance, Thompson notes. Leptin is a hormone that signals when you’re full, and when that signal isn’t transmitted properly, it can lead to overeating. Leptin resistance is also related to higher levels of insulin in the blood, which she says block the uptake of leptin in the brain stem, aka the “lizard brain,” where the base needs of survival are grounded. This puts the drive for survival in charge, which leads those who are susceptible to such urges to overeat.  

Thompson writes that overpowering food cravings occur when the bingeing mechanism in the brain is triggered. This particular challenge originates in the nucleus accumbens, a section of the brain where pleasure resides. Over time, overindulging causes the nucleus accumbens to downregulate. In people with substance dependencies, this is when tolerance increases and you need more and more of the stimuli to elicit the desired effect. Eventually, the desired effect disappears all together, and the brain demands more and more of the stimulus just to maintain a sense of normal. The same thing happens with food addiction, Thompson argues.

The BLE plan includes no specific requirements for exercise. In fact, Thompson writes that she discourages people from adopting a new exercise program within the first four or five months of being on the BLE program because it can drain your willpower levels. She also notes that some Bright Liners have struggled with exercise addiction in the past. She’s found that among people who’ve attended her Boot Camp sessions, “the people who insist on continuing to exercise lose the least amount of weight. They’re overtaxed. They can’t keep their lines bright, and it all unravels from there.”

After a few months, once you’ve established your bright lines or you’ve lost all the excess weight, you can then begin exercising again, Thompson notes. “What we want at Bright Line Eating is to get to a place where exercise is valued for all its health benefits but totally and completely uncoupled from weight loss in dieters’ minds,” she writes.

The BLE program also encourages detailed journaling of your daily food journey, both in planning for what to eat the next day and in recording what you did today.

In addition to the books Thompson has written, there’s also a membership component to the Bright Line Eating approach, which provides access to all BLE courses and coaching and an online community of BLE followers. Video tools, written resources, meal plans, shopping lists and one-on-one calls are also available to members. Membership costs $39.99 per month on the monthly plan or $399.99 per year on the annual plan. Both plans come with a two-week free trial period.

Thompson has published a book of BLE recipes called “The Official Bright Line Eating Cookbook: Weight Loss Made Simple.” It outlines a simple daily food plan for three meals that includes:

Whole grains such as oats or brown rice are in bounds on this plan. Potatoes and sweet potatoes are also counted as a grain in the BLE universe. Grains should be limited to one ounce when measured dry.

Proteins can include plant-based proteins such as tofu and tempeh, Greek yogurt, seeds, cheese, eggs, beef, chicken and any other animal protein, except bacon. Thompson says that when handling cooked proteins, you should measure your food after it’s been cooked, as meat can shrink by 25% to 50% during cooking. She also recommends checking the package carefully before using any processed meats such as hot dogs, sausage or bacon because sugar or flour is often added to these products.

Fruit should be measured at about 6 ounces for a serving. Approved fruits include apples, kiwi, bananas, grapefruit, grapes, oranges, berries, apricots, pineapple and many others.

Vegetables can include virtually any kind of vegetable, whether cooked or raw. If you’re cooking them, weigh your portion afterward because they often shrink during cooking. Canned or frozen veggies are fine, but check the package to be sure there’s no added sugar.

When making an 8-ounce salad, start with about 2 to 3 ounces of lettuce and add another 5 to 6 ounces of various vegetables on top. Croutons and other flour-based crunchy additions are banned, and don’t add dried fruit or salad dressings that contain sugar or flour.

If you’re using olive oil or another fat in your cooking, be sure to measure that out and count it as your fat serving for the meal. One tablespoon is a serving.

You can have as much water and herbal teas as you want on the BLE program. Coffee and caffeinated tea, however, should be limited because the program views caffeine as a triggering substance that can lead to cravings for some people. If you do consume coffee or caffeine-containing black or green tea, make sure it contains no added sugar. Alcohol is a no-go on the BLE plan because it’s high in sugar and can reduce your willpower to resist off-limit treats, according to Thompson.

Thompson writes that not everyone will be able to maintain their bright lines all the time. Instead of feeling guilty or dejected, it’s important to get back on track right away; rather than resume your diet tomorrow, she writes that you should “rezoom” your diet at the very next meal. When slip-ups occur, she encourages you to show yourself some compassion and seek out social support from other dieters, family or friends.

Learning to “rezoom” often might not be a sustainable solution, though. Sauza says that the guilt associated with eating forbidden foods may affect a person’s motivation to continue working towards a healthier lifestyle. Overall, he says this is typically why fad diets do not work, realistically they do not teach how to eat balanced or healthily for years to come.

Before getting started on the BLE program, Thompson recommends visiting your doctor to make sure this approach won’t exacerbate an existing medical condition or interfere with any medications you might be taking.

It’s also worth noting that while Thompson posits this diet can be a good approach for people who’ve struggled with food addiction and eating disorders in the past, generally speaking, people with a history of eating disorders should avoid restrictive diets.

Restrictive diets that eliminate certain foods or whole food groups can also backfire and lay the groundwork for a binge. A binge “would be categorized as eating a large amount of food in a short period of time,” says Erin Holley, a registered dietitian with the Ohio State University Wexner Medical Center in Columbus. Binge eating is often accompanied by feelings of being out of control or like you can’t stop eating.

With BLE, the aim of the prescribed restriction is to eliminate those binges and the emotional rollercoaster that often accompanies them. Over time, though, it may become difficult to avoid the pull of certain foods that have been designated as forbidden.

Some dieters have found weight loss success with BLE, as Thompson shows with various testimonials and case studies throughout her book. However, Vaca-Flores says, “in my opinion, BLE is not a healthy approach for weight loss. Regardless of how you put it, Bright Line Eating is a diet, and as we know, dieting doesn’t produce long-term weight loss results for most people.” This has been evidenced in several studies over the years, with a recent and cogent example being a large study of 14 popular diets published in BMJ in 2020 that found that diets don’t work for the majority of people. The problem is that while weight loss occurs initially, over time, the body compensates and weight returns.

In addition, Vaca-Flores notes that “imposing strict rules such as prohibiting snacks and added sugars isn’t sustainable or enjoyable. Labeling certain foods as prohibited will make us want them more, which simply defeats the purpose of a diet that is designed to address food addiction.”

Most dietitians suggest making small, incremental changes that can last a lifetime. Instead of slashing calories to drop weight as quickly as possible, they recommend you lose weight slowly and combine a healthy diet with plenty of physical activity. This approach tends to be a more sustainable way of losing weight and keeping it off for good.

While it’s entirely possible to lose weight without exercise, most dietitians and doctors say that exercise should be part of your weight loss. Exercise burns calories, but more importantly, it offers many health benefits, including improved cardiovascular health, strength and sleep. Exercise also helps you maintain muscle as you lose weight, and it can boost your metabolism. This can help offset the natural tendency the body has to lower the metabolic rate in a reduced calorie environment like a diet.

Sauza says that he wouldn’t recommend any eating approach or diet that requires complete restriction of food types. He also says that “for anyone with a history of an eating disorder, restrictive eating, chronic dieting, or any other type of restrictive habit, they should avoid this approach to eating.”

If you do try the BLE plan and find that it doesn’t work for you, you may want to meet with a registered dietitian or a therapist to help you work through the yo-yo dieting cycle. “Don’t be afraid to seek help for these issues (related to) eating,” Holley says. “There is no shame in reaching out for help.”