Weight, eating disorders and body image

Why diets don’t work: restriction, binge eating and intermittent fasting

If dieting has left you preoccupied with food, “out of control” around certain foods, or as though you have failed yet another plan, the problem is not a lack of willpower.

Reviewed September 2026

Most diets work in the short term by creating a calorie deficit. The difficulty is that a plan which is highly restrictive, rigid or unpleasant is often very hard to live with—particularly when life is busy, stressful or emotionally demanding. Our bodies and minds also respond to deprivation in understandable ways: hunger increases, food becomes more attention-grabbing, and foods labelled “off limits” can feel increasingly urgent.

A more useful question is not simply “Which diet is best?” but “What way of eating can support my health, my relationship with food and my life over time?”

What do we mean by “diet”?

A therapeutic eating plan can be an important part of managing a health condition. In everyday language, however, dieting often means trying to lose weight through rules such as cutting out whole food groups, avoiding particular foods completely, skipping meals, fasting to compensate for eating or setting very low calorie targets.

These rules can initially feel reassuring because they provide certainty. But they can also make eating feel like a test of character rather than a normal, flexible part of life.

Why dieting is difficult to sustain

Weight is influenced by far more than motivation. Genetics, medical conditions, medications, sleep, stress, food access, income, culture, activity, appetite and life stage all matter.

When food intake is reduced, the body adapts. Hunger and thoughts about food may become stronger, and it can become harder to feel satisfied. A strict plan may also leave little room for social occasions, illness, travel, family meals or simply enjoying food. When the rules eventually become too difficult to maintain, people often interpret this as personal failure and restart with even stricter rules.

The restriction–binge cycle

Restriction → increasing hunger and food preoccupation → eating beyond comfort or feeling out of control → guilt or shame → renewed restriction.

The cycle—not a lack of discipline—is often the problem.

How restriction can contribute to binge eating

A binge-eating episode involves eating while experiencing a sense of loss of control. It is different from simply enjoying a larger meal, eating more at a celebration or having an occasional unplanned snack.

Restriction can be physical, such as not eating enough or going for long periods without food. It can also be psychological: deciding that certain foods are forbidden, feeling guilty for eating them, or believing that one food choice has “ruined” the day.

When a person is very hungry, tired, stressed or has been trying hard not to eat a desired food, eating can become more urgent and less flexible. Once a dietary rule is broken, an all-or-nothing thought—“I have already failed, so I may as well keep eating”—can make the episode feel worse.

This does not mean that everyone who diets will binge eat, and binge eating is never caused by one factor alone. Mood, trauma, body image concerns, depression, anxiety, life stress, food insecurity and previous eating-disorder symptoms can all play a role. However, research consistently identifies dieting and fasting as important risk factors for some people. A large prospective study found that fasting was associated with later onset of recurrent binge eating and bulimic symptoms.

It is important not to oversimplify the evidence. A review of clinically supervised very-low-energy dietary interventions did not find that severe restriction inevitably triggered binge eating; outcomes varied, and binge eating sometimes reduced during treatment. This is very different from saying that unsupervised restriction is safe or suitable for everyone, particularly someone with current or past eating-disorder symptoms.

What about intermittent fasting?

Intermittent fasting is an umbrella term for eating patterns that alternate periods of eating and fasting. Examples include time-restricted eating, such as eating within an eight- or ten-hour window, alternate-day fasting and fasting on selected days each week.

It is often presented as a special metabolic strategy. In reality, intermittent fasting can lead to weight loss when it helps a person eat less overall. It does not appear to have a reliably superior effect on weight loss compared with other approaches that create a similar reduction in energy intake.

A recent Cochrane review found that, compared with usual dietary advice, intermittent fasting may make little to no difference to weight loss or quality of life in adults with overweight or obesity. As with other approaches, results vary substantially between people and long-term evidence remains limited.

Is intermittent fasting related to binge eating?

Intermittent fasting is not an eating disorder, and it does not cause binge eating in every person who tries it. Some adults find a time-limited eating pattern neutral or helpful.

However, fasting can be risky for people who are vulnerable to binge eating, loss-of-control eating or other eating-disorder behaviours. Research has found an association between longer periods without eating and a higher likelihood of binge eating the following day among people with binge-eating symptoms.

Association does not prove that fasting caused the binge eating. Some people may turn to fasting because they are already distressed about food or weight. Nevertheless, when fasting leads to intense hunger, preoccupation with food, overeating during the eating window, guilt or attempts to “make up for” eating, it is a sign that the approach is not supporting wellbeing.

When intermittent fasting needs individual advice

Intermittent fasting is generally not an appropriate self-directed strategy for people who:

currently experience binge eating, purging, compulsive exercise or significant food anxiety;
have a current or past eating disorder;
are pregnant, breastfeeding, a child or adolescent;
use diabetes medication that can cause low blood glucose; or
have a medical condition where meal timing needs individual guidance.

Discuss fasting with your GP, dietitian or treating team before starting it if any of these apply.

A more helpful way forward

For many people, the first step out of the restriction–binge cycle is not another set of food rules. It is building a more regular, adequate and satisfying eating pattern.

This may include:

eating regularly enough that you do not become extremely hungry;
including carbohydrate, protein, fats and enjoyable foods;
choosing meals and snacks that are satisfying rather than merely “allowed”;
practising flexibility after an unplanned food choice instead of compensating;
becoming curious about hunger, fullness, emotions and eating triggers without judgement; and
seeking support for stress, body image concerns or eating-disorder symptoms.

Health matters, and nutrition can support health in meaningful ways. But sustainable care does not require punishment, fear of food or perfect eating. A plan that protects your relationship with food is far more likely to support your health over the long term.

When to seek support

Speak with your GP or an Accredited Practising Dietitian if eating feels out of control, you are regularly restricting or fasting to compensate for eating, or food and weight thoughts are taking up significant mental space. Binge-eating disorder is treatable and can affect people in bodies of all shapes and sizes.