I want to talk about cheating, and about a word I would rather retire: the “cheat day.”

The psychology of lapses and cheat days
A lapse is a single event. A relapse is a decision.

The language matters more than it looks. Calling a meal “cheating” frames eating as a moral contest you can win or lose, and casts you as the sort of person who breaks promises. Almost nobody responds well to that framing — and the research on what happens next is remarkably consistent.

The abstinence violation effect

The behaviour that undoes more weight loss efforts than any food ever has is not overeating. It is what people do in the hour after overeating.

Psychologists studying addiction described this decades ago as the abstinence violation effect: when someone who has committed to a rule breaks it, they experience the breach as evidence of a permanent personal failing rather than as a discrete event — and that interpretation, not the breach, predicts full relapse.1

In eating research the same pattern shows up as counterregulatory eating. In classic experiments, restrained eaters given a milkshake “preload” subsequently ate more in a taste test than restrained eaters given nothing — while unrestrained eaters ate less, as you would expect. Having already broken the rule, the dieters ate as though the day was written off.2

One biscuit costs about 60 calories. The belief that the day is now ruined costs considerably more.

Lapse is not relapse

The distinction is worth learning properly, because it is the difference between a bad afternoon and a bad year.

  • A lapse is a single deviation. You ate the cake at the office. It happened.
  • A relapse is the abandonment of the plan that follows — usually triggered not by the cake but by the interpretation of it.

Every person who has successfully maintained weight loss has lapsed, repeatedly. What they learned to do was resume at the next meal rather than the next Monday.

The traps we reliably fall into

The all-or-nothing rule. Rigid dietary restraint — strict rules, forbidden foods, exact adherence — is associated with worse outcomes and more disinhibited eating than flexible restraint, which permits planned deviation without moral weight.3 The person with a short list of banned foods is more likely to binge than the one who eats a slice of cake at a birthday without comment.

Licensing. A good decision creates permission for a bad one. People who exercise commonly overestimate what they burned and reward themselves with more calories than they spent — a phenomenon documented well enough that it undermines exercise-only weight loss programmes. Run the numbers in the activity calculator and the exchange rate is sobering.

The planned cheat day. A whole day of unrestricted eating can wipe out a week’s deficit. Six days at 500 calories below maintenance creates a 3,000-calorie deficit; a genuinely unrestricted day can add 2,000 to 3,000 back. This is why people describe eating “perfectly all week” and losing nothing.

Emotional eating. Distress reliably increases intake of highly palatable food, and equally reliably degrades the deliberate control needed to resist it. This is neither weakness nor greed; it is a well-mapped physiological response. But it does mean that a plan with no provision for bad days is a plan with a hole in it.

What to do instead

  • Retire the word cheat. You ate a scone. You did not betray anyone.
  • Plan the deviations. A planned indulgence is part of the diet. An unplanned one is a lapse. The same scone in the same mouth — the difference is entirely whether it was chosen.
  • Use flexible rather than rigid restraint. No banned foods; portions and frequency instead.
  • Build an if-then plan. “If there is cake in the staff room, then I will have a slice with coffee and not take a second.” Forming specific implementation intentions in advance substantially improves follow-through, because the decision is made before the moment arrives.4
  • Have a rule for after. Mine is simple and I give it to every patient: the next meal is normal. Not smaller in penance, not skipped. Normal.

Faithfulness here does not mean never deviating. It means not walking out on yourself when you do.

Dr. Gily Ionescu, MS MD

References

  1. Marlatt GA, Gordon JR. Relapse Prevention: Maintenance Strategies in the Treatment of Addictive Behaviors. New York: Guilford Press; 1985. The original description of the abstinence violation effect and its role in full relapse.
  2. Herman CP, Mack D. Restrained and unrestrained eating. J Pers. 1975;43(4):647–660. doi:10.1111/j.1467-6494.1975.tb00727.x The preload experiments demonstrating counterregulatory eating in restrained eaters.
  3. Westenhoefer J, Stunkard AJ, Pudel V. Validation of the flexible and rigid control dimensions of dietary restraint. Int J Eat Disord. 1999;26(1):53–64. Evidence that flexible restraint predicts better outcomes than rigid restraint.
  4. Gollwitzer PM, Sheeran P. Implementation intentions and goal achievement: a meta-analysis of effects and processes. Adv Exp Soc Psychol. 2006;38:69–119. doi:10.1016/S0065-2601(06)38002-1 Meta-analysis supporting if-then planning as an effective behaviour change technique.