We commonly assume that restrained eaters find it easier to lose weight. Surprisingly, the opposite is true.

Instead, dieting often predicts weight gain, along with maladaptive eating behaviors such as bingeing – not to mention unpleasant emotional states like guilt and eating-related stress.

Introduction

Ask anyone these days about their food intake and you’re likely to hear they’re restricting it somehow. In the United States alone, about 45 million adults claim to be dieting every year (1).

Then why are so many folks still overweight? Something just doesn’t add up. On the surface it seems that diets don’t work.

Dietary restraint

In this article we’re going to talk about something called dietary restraint. So let’s begin with a definition. In other words, what exactly does “dietary restraint” really mean?

Is it:

A: putting a padlock on your refrigerator;

B: never taking second helpings;

C: having your jaw wired shut; or

D: the intention to eat less for the purpose of losing or maintaining weight?

Okay, it’s pretty obvious that the answer’s D – but I’ll bet there are numerous dieters who have tried the others.

In the realm of eating behavior research, the term dietary restraint is defined as “the intentional and sustained restriction of caloric intake for the purpose of weight loss or maintenance” (2).

In other words, it’s that little voice in the back of your head that says: “You really shouldn’t eat those chips and that bowl of ice cream, because your class reunion is coming up soon.”

Sound familiar?

But here’s something that might surprise you: Although this voice may seem to be giving you sensible advice, in fact, its nattering may be counterproductive. It might even goad you into overeating or bingeing.

There’s a sobering thought.

Now, we’re not trying to suggest that you should indulge your every whim for chips or ice cream. But we are saying that a highly restrictive attitude towards food doesn’t help.

How do you measure dietary restraint?

Good question!

Measuring emotions and visceral states (like the feelings of being tense or tired) can be extremely tricky. But you know those scientist types. They think everything can be measured. So they’ve figured out several different methods for doing this.

Researchers can use several types of dietary restraint questionnaires, which vary in usefulness and validity, and ask questions on eating behavior such as “Do you often lose control when eating?” and “Are you currently trying to lose weight?” (2, 3).

With each assessment tool, the results are reported as scores on a scale. The higher a person’s score on the restraint scale, the greater his or her intention to lose weight is thought to be.

OK, makes sense. You’d expect that dietary restraint would mean people were controlling their weight well and making smart food choices. But here’s the thing:

High scores on restraint scales (in other words, people who are “dieting”) often predict weight gain rather than weight loss – and can even predict the onset of future bingeing (2).

Wait a minute! For years, people who want to lose weight have been told to restrict their calories. And now it turns out that calorie restriction can lead to weight gain? What are we supposed to make of that?

The downside to calorie restriction

You’ve probably heard that when you’re craving a particular food, it’s often smarter to give into that craving and eat a small portion, rather than trying to substitute with a knock-off, less tasty alternative.

You just won’t be satisfied with the sub-par option. And in trying to make up for what you’re missing, you’re likely to consume more calories than if you’d eaten the treat you really wanted.

This suggests how dietary restraint can backfire. If you’re actively trying to control what you eat, somewhere along the line, you’re going to feel dissatisfied with the foods (or the quantities of food) you permit yourself. And you’re going to be tempted to give in to your urges.

What’s more, when you do give in, you’re probably going to feel pretty badly about yourself, because you haven’t done something that you intended to do – restrict calories.

Research question

This week’s review looks at what dietary restraint involves, and how it tends to affect us.

The researchers wanted to learn why people who try to restrict calories often fail to lose weight. (Instead, restrictors develop a poor relationship with food, which frequently leads to weight gain rather than weight loss.)

The researchers hypothesized that dietary restraint actually just makes people feel guilty instead of lowering their food intake.

Methods

This study consisted of a series of three separate experiments, each following the same basic procedure, to test whether high levels of restraint make people feel guiltier after eating.

The first study used a quasi-experimental design: no pre-test, no control, no random assignment. Researchers simply wanted to test whether or not restraint levels were linked with feelings of guilt after the subjects were unobtrusively exposed to food.

The second experiment collected baseline data, making the design stronger (i.e. the data more robust), and the third experiment included baseline data with an additional post-intervention questionnaire. Thus, the experiments built upon one another, as the researchers sought progressively to rule out different explanations for or influences on the results.

In each of the studies, the researchers selected a female student population, since female students are at high risk for developing disordered eating patterns, and also because restricting calories/dieting is common in this particular population.

The study’s set-up involved a mock consumer taste test for a supermarket chain. After reading this you may you think twice next time you scarf down those yummy samples at Costco or Whole Foods. You never know who’s watching you and taking notes – like a group of scientists in white lab coats with big clipboards.

Study 1

Subjects

57 female students with an average age of 21 and BMI of 21.8 (normal is 18.5 to 24.9), participated in exchange for course credit or a small sum of money.

Procedures

The study was set up as a mock consumer taste test for a large supermarket chain. Subjects could only participate if they had not eaten for at least two hours, so the researchers could standardize satiety ratings.

To ensure the subjects wouldn’t be inhibited, they were left alone in a room for 10 minutes to complete the taste test and product evaluation. The design was crafty because subjects were offered a variety of high and low calorie foods to sample, giving them control over their caloric intake.

Researchers weighed the sample bowls before and after the test to calculate how much the subjects ate. They also assessed the participants’ emotional states, including guilt, as well as their level of dietary restriction.

Measures

Dietary restraint – A ten question instrument was used to assess the participant’s level of restraint. Example questions included: “How often do you diet?” and “Do you give too much time and thought to food?” The answers were coded on a five-point scale. The higher the score, the higher the level of restraint, with scores ranging from a low of 10 to a maximum of 49.

Guilt – Participants were also asked questions about their emotional and visceral states, including how much guilt they experienced at that moment on a scale from 1 (not at all) to 5 (a lot).”Guilt” was hidden among a list of 25 other emotional states (such as “tense” and “tired”) so it wouldn’t be obvious to participants that the researchers were especially interested in that emotion.

Food intake – The mock taste test consisted of four different snacks: two high-calorie snacks (chips and chocolate-covered peanuts) and two low-calorie snacks (crackers and apple slices). Because the researchers weighed the bowls before and after the test, they could calculate how many calories participants ate, and of those, how many came from each category.

Study 2

Subjects

43 female students with an average age of 23 and BMI of 22.6 (normal is 18.5 to 24.9), participated in exchange for course credit or a small sum of money.

Procedures

The procedures were the same as in Study 1, with the addition of baseline data collection on measures of guilt and other types of negative emotion. These measures were added to rule out other potential explanations for the levels of guilt discovered in Study 1, and to be certain that guilt was associated with eating rather than being a typical emotional state for the participants.

Measures

Identical to Study 1, with the addition of baseline data collection.

Study 3

Subjects

42 female students with an average age of 21 and BMI of 20.9 (normal is 18.5 to 24.9), participated in exchange for course credit or a small sum of money.

Procedures

The procedures built on Studies 1 and 2, with a further attempt to rule out other explanations for the levels of guilt that were measured. To more rigorously test whether the observed guilt was related to eating, explicit questions addressing eating-related guilt were asked after the taste test.

Measures

Baseline guilt data collection, food intake, restraint and the additional parameter of eating-related guilt. Researchers revealed this by asking questions such as “How guilty do you feel about eating the snacks?” with answers rated on a five-point scale ranging from 1 (not at all) to 5 (very much).

Results

The researchers wanted to find out if people who score high on dietary restraint scales do actually eat less and/or if they experience higher levels of guilt-related feelings when they do eat.

Study 1

This study showed that high restraint scores did not predict total caloric intake, but that they did significantly predict guilt.

Those who felt guilty felt that way regardless of how many total calories they’d eaten, and whether they’d eaten high or low calorie foods. This suggests that the observed guilt was a function of high dietary restraint scores rather than actual food intake.

Study 2

The results of this study were similar to those in Study 1 in that restraint did not predict caloric intake but it did predict guilt. Additionally, the guilt was associated specifically with eating and not with an overall negative state of mind.

Study 3

The results of this study replicated the other studies and extended the findings with the post-taste test questions on guilt. Those who scored high on restraint also experienced the highest levels of guilt after eating.

Conclusion

While it’s difficult to draw solid conclusions based on one eating episode, these studies clearly indicate a strong correlation between high scores on dietary restraint and feelings of guilt.

What’s more, contrary to what we might expect, restrained eaters do not eat less than people who aren’t trying to restrict their intake. It’s true: Diets don’t work!

And to make matters worse, the guilt the restrained eaters experience decreases their pleasure in eating and may lead to feelings of failure, as well as greater levels of anxiety, depression, and reduced self-esteem.

It’s a vicious cycle: A person intends to eat less, but fails in the attempt. Failure to eat less leads to guilt, and redoubled attempts to restrict – which, you guessed it, typically lead to more failure. Soon you can add reduced self-esteem and self-efficacy to the mix. This in turn may lead to increased “comfort” eating. And so it goes.

Additional research might consider multiple eating episodes and could focus on different populations. Future studies might also adopt measures such as time diaries to see if guilt occurs after each eating episode.

Bottom line

Eating should be a source of pleasure. It should feel really good to nourish your body.

Unfortunately, soon after early childhood our emotions and our environment start muddling up our hunger and fullness signals. We start depending on complicated rules about what, when and how much we should eat – leading to dietary restriction, which unfortunately often backfires.

So keep it simple. Focus on nourishing yourself and adding value to your body, rather than on being “good” or “bad”.

Eat slowly – one of the core habits in Precision Nutrition’s Coaching – over time, we can learn our own internal appetite and fullness cues… and learn to trust our bodies to know how much food we genuinely need.

Instead of restricting, look for more — more quality, that is. This means lean protein, vegetables, fruits, and slow-digesting, high-fiber carbohydrates. Balance the amount to match your level of activity, stage of life and unique needs.

Question what you believe about the “right” way to lose weight (i.e. rigid rules, control, and self-criticism). Lose the guilt and restrictive mindset, because as this study demonstrates, it’s a recipe for dieting disaster.

Eat, move, and live… better.

Yep, we know… the health and fitness world can sometimes be a confusing place. But it doesn’t have to be.