Why Focusing on 'What to Eat' Beats 'What to Avoid'

For decades, the advice on diets has mostly been based on one word: STOP. Stop eating fat. Stop eating eggs. Stop eating butter. Stop eating red meat. Stop eating bacon. Stop eating carbs. Stop eating processed foods. It goes on and on and on. . It's quite understandable why it's like this. It's simple. It makes sense. It follows logic. But it rarely works.

If your cholesterol is too high, you just need to be told by a doctor to eat less cholesterol, you'll follow that advice, and then everything will be fine. Or if you're overweight, your doctor just needs to tell you to eat less food, and you'll follow that advice, and you'll then be able to maintain a healthy body weight for the next 60 years. No problem. Is it that easy, right?

If it were that easy, Hippocrates would have eliminated obesity 2,500 years ago. If all we had to do was say "stop doing" something, we'd have no crime, no speeding tickets, no puppy training classes or weight loss medication.

Banning, barring, eliminating or restricting doesn't seem to be enough by itself (in our opinion). Trial after trial, both in the lab and in the real-world, have shown that elimination-focused diets and dietary advice do not have a good record of compliance. They do work in some specific cases, but we see little evidence of it working universally.

Maybe there is a better way? Instead of fighting hard-wired human biological instincts with willpower, silly games and mind-tricks, why not try to align human behaviour and human physiology together?

In this article, we'll set out some of the theory behind why we think focusing on what to eat is better than focusing on what to avoid.

Reason #1. People Hate Being Told What (Not) to Do

People don't like restrictions or being told what to do. Especially if the consequences aren't immediate, obvious or severe.

"Additive bias"

Think about the last time you gave (or received) advice from someone. Did they tell you to start doing something (i.e., "take this", "do this", "do that", "why not try this" etc.) or did they tell you to stop doing something that you're already doing?

When asked to fix or improve a situation (for example, your own health), humans tend to have "additive bias". This is where they usually default to adding or doing something to solve a problem rather than removing or stopping something. We even do this when removing or stopping something is faster, cheaper, simpler, or better.^[1]

So it seems that our natural problem-solving tendencies are to add things rather than remove them. So, for health advice and dietary recommendations, "add X to your diet" seems to be more natural than "eliminate Y and restrict Z".

"Gain-Frame" vs "Loss-Frame"

In psychology, the way a piece of advice is worded is called "framing", and it seems to alter how people respond to it.

• The Gain Frame: Focuses on what you should add or gain (e.g., if you eat oats for breakfast, you'll gain cholesterol-lowering fibre).
• The Loss Frame: Focuses on what you must sacrifice or avoid (e.g., if you eat white bread, you'll increase your risk of diabetes).

Gain frame messaging appears to be more effective at promoting general "preventative" healthy behaviours. Loss framing works as well, but in much more limited circumstances. Loss framing can be very effective in specific cases, which have high risks and clear and severe consequences. Examples include:^[2][3]

• Telling a patient with severe celiac disease that they must strictly avoid gluten.
• Telling a person with an anaphylactic peanut allergy they must avoid peanuts.
• Telling a person with uncontrolled diabetes that they should restrict the amount of refined sugars they eat.

Loss framing works here because the consequences are immediate, severe and unambiguous. However, applying emergency-style instructions to everyday health advice for healthy people is a folly (in our opinion).

The negative effects of smoking, eating a poor diet, not brushing your teeth, and being sedentary aren't immediate, obvious or severe. It usually takes years before they start noticeably affecting your health, so people can't link them as easily to one another. So, for broader lifestyle upgrades, we don't see treating everyday eating as a constant medical emergency.

Sure, saying "sugar is poison" or "processed foods are as bad as cigarettes" might trick or scare some people into making some temporary changes that may be healthy. But we generally think that the inaccurate alarmist rhetoric psychologically burns people out, and it undermines trust in the long-run.

For encouraging dietary changes in the general population, we think gain-framing is the best for long-term adherence.

It's just about willpower. Or is it?

In the scientific community, it is thought that willpower and self-control are not just character traits. They are more like a "resource" that you have, and a limited one at that. So, willpower and self-control are fixed; they can be weakened and depleted with use.^[4]

Think of it as everyone having a certain amount of "mental energy" in a given time period, and once that is used up, willpower and self-control start to deteriorate.

Trying to avoid certain foods, counting calories and macros, and forcing yourself to say no all day requires continuous mental effort and willpower and leads to decision fatigue. It is exhausting and difficult to maintain long-term.

Whereas focusing on eating high-nutrient-density, low-energy-density, and high-fibre foods, which fill your stomach and keep your blood sugar levels low, will make those "bad" foods less appealing. There's less "mental energy" involved.

It's also a lot easier to say no to food when you aren't as hungry; it requires less willpower, self-control and mental energy. In total, we think that generally it requires less "mental energy" and effort to direct your focus on the healthy things you should be eating rather than the unhealthy things you shouldn't be eating.

Reason #2. Unintended Consequences of Restrictions

Eating disorders and unhealthy relationships with food

A major overlooked danger of "what to avoid" nutritional advice is its potential to create unhealthy relationships with food. The "avoid" messaging relies on strict dietary controls. Foods are divided into "good" or "bad", "clean" or "dirty", "allowed" or "forbidden", "cheat" vs "non-cheat", or "red", "amber" and "green".

Rigid dietary control is linked to food anxiety, obsessive thoughts around eating and possibly an increased risk of eating disorders. We think that a meal should be there to nourish and be a source of enjoyment, rather than a psychological challenge and anxiety-inducing event.^[5][6]

Focusing on what to eat promotes flexible dietary controls ("guard rails"). Encouraging people to eat healthy, nutrient-rich foods, rather than eliminating certain foods, is less psychologically burdensome.

When you're focusing on what to eat, no food is "poison", forbidden, or red-zoned. Healthy food is simply prioritised on your plate. More flexible diets are generally more sustainable and associated with better health outcomes and healthier eating habits.^[5]

A crisis of confidence

What to avoid recommendations have more downside risk. Particularly if they are difficult to follow. If you're avoiding all ultra-processed food, eating that slice of cake means 100% failure. It is an all-or-nothing approach. So when you fail, it will knock your confidence and potentially cause you to abandon the diet entirely. Or you start on a course of yo-yo dieting.^[7]

Focusing on "what to eat" has a lower downside risk, as "failure" is a lot less obvious and not as easy to do. You also have an opportunity to correct it later on in the day: if you miss one of your daily servings of legumes at lunch, you can just eat them in the evening or the next day. However, there's no way back if you eat a single cookie on your cookie-free diet — that's the day ruined!

Being able to successfully follow a diet generally improves self-confidence (and thus health outcomes). This in turn makes you more likely to follow diets and healthy eating patterns, creating a positive feedback loop. So the easier the healthy diet is to follow (or the less easy it is to fail), the better the long-term health prospects are.^[8]

The rebound effect

Forbidden fruits taste the sweetest, right? Well, the research supports it. Strict controls around "forbidden foods"(which are usually tasty already) trigger stronger cravings. They become more tempting and more difficult to avoid.^[9]

Secondly, if or when even a small piece of the "forbidden food" is inevitably eaten, it then goes on to trigger the "what the hell effect". This is where you end up abandoning the diet, because it has been"ruined", which then gives the green light to binge eat the foods you've been trying to avoid. So 200 forbidden food calories can turn into 2,000 in a single day.^[10]

The health halo

When recommendations are too vague and focused on elimination, they are frequently replaced with equally bad or possibly worse alternatives. For example, in the 1990s, when reducing dietary fat was aggressively promoted, the food industry responded with "low-fat" products that replaced the full-fat ones with refined sugars and processed starches. So in some cases you had healthy fats replaced with unhealthy processed ingredients.

More recently, people have been on diets that dramatically cut out carbohydrates, replacing whole fruits, legumes and wholegrains with processed foods packed with unhealthy fats, artificial flavourings and sweeteners. Keto bread anyone?

Clear "what to eat" recommendations make this less likely because you are adding healthy whole foods (e.g., oats, legumes, fruit and vegetables) rather than creating a new market for substitute foods.

Reason #3. The "Crowding Out" Effect

Adding healthy food to your diet has two effects. The first one is the obvious one: eating more healthy, nutrient-rich foods brings more nutrients into your body. But secondly, (and less obvious) eating healthy foods also "crowds" the unhealthy foods out of your diet. The latter is overlooked.

Humans tend to eat a surprisingly consistent "amount" of food each day, irrespective of its calorie or nutrient content. So, when you add healthy, whole foods that are watery and fibrous, they physically displace the unhealthy, high-calorie, nutrient-deplete foods on your plate.^[11]

So you get the double benefits: you add something "healthy" and displace something "unhealthy". There are two reasons why this happens:

Stomach Stretch

High-volume foods like oats, vegetables and beans contain a lot of water and fibre per gram, and have a low amount of calories per gram of food. So, when they enter your stomach, they take up a lot of room and stretch your stomach. The stretching sends a signal to your brain to tell you that you are full and to stop eating. So you end up eating fewer calories overall.^[12]

Gut Peptides

As the bulky fibre-rich food reaches your gut, they respond by releasing "fullness" hormones like Glucagon-like Peptide-1 (GLP-1), Gastric Inhibitory Peptide (GIP), cholecystokinin (CCK) and Peptide-YY (PYY). These hormones reduce the amount of food you eat, slow down digestion, keep blood sugar levels low and reduce cravings for unhealthy junk foods.^[12]

Putting it into Practice