The Last Supper Effect: Eating More Before a Diet Starts

It is Sunday night. The new plan starts tomorrow. So tonight, you eat. You eat the ice cream, the pizza, the biscuits, the crisps. You eat things you do not even like very much, because tomorrow they will be gone.

This is one of the most recognizable patterns in dieting, and researchers have a name for it. This article looks at the last supper effect, the evidence behind it, and why it reliably appears the night before a fresh start.

The situation

You have decided to change how you eat. There is a start date, usually Monday, or the first of the month, or after the holiday. In the hours before that date, you eat more than you have in days. By the time you go to bed, you feel uncomfortable and defeated, and you have not even started yet.

What the research says

• Anticipated restriction increases intake. In a key study, restrained eaters who were told they would start a diet the following week ate significantly more ice cream in a taste test than those given no such instruction. Unrestrained eaters were unaffected by the same information. The mere anticipation of restriction was enough to drive up eating in people who already monitored their food [1].
• Dieting and bingeing are connected. In an influential paper, Polivy and Herman argued that dietary restraint paradoxically causes overeating. The cycle works like this: restriction creates psychological deprivation, which increases the likelihood of breaking the diet, which creates guilt, which leads to stricter restriction [2].
• Rigid control predicts worse outcomes. In a study validating measures of flexible versus rigid dietary control, rigid control was associated with higher body weight and more frequent binge episodes. Flexible control, where no food is completely banned, was linked to lower weight and fewer problems [5].
• Long-term maintainers are less rigid. In a comparison of people who had maintained weight loss and those who had not, the maintainers reported less use of strict dietary rules and more acceptance of occasional lapses [4].

How strong is this evidence? The anticipation study is small (one lab session) but has been replicated in concept. The Polivy and Herman model is widely cited and supported by later work, though not all researchers agree on the direction of causality. The flexible-versus-rigid findings are consistent across several studies.

A fictional example

This example is fictional and illustrative. Sam is not a real person.

Sam decides on Wednesday that he will start eating differently on Monday. By Friday he is already thinking about it. He eats normally on Saturday morning, but by Saturday night the urgency kicks in. He orders a large takeaway, eats chocolate afterwards, and finishes with toast and butter at midnight. Sunday follows the same pattern. By Monday morning he feels bloated and disgusted.

When he starts the plan, he is already depleted. He lasts four days. On Thursday he eats a biscuit at work, declares the week ruined, and starts thinking about next Monday.

Sam notices that the gap between plans is not reckless eating. It is last-supper eating: frantic, joyless, driven by the knowledge that something is about to be taken away. He wonders what would happen if nothing were being taken away at all.

Questions to examine the pattern

• What am I afraid I will not be allowed to eat?
• Would I eat this much tonight if no plan started tomorrow?
• How many times have I had a “last supper” before a diet?
• What happens in the first few days of the plan? How long does it usually last?
• What if there were no start date and no forbidden foods?

Why the last supper makes sense

The pattern is not irrational. If someone told you that bread would be unavailable for three months, you would probably eat some bread tonight. The mind responds to anticipated scarcity by stockpiling, even when the scarcity is self-imposed. The problem is that each round of last-supper eating makes the diet feel more necessary, which makes the next last supper more intense. It is a cycle that generates its own fuel.

A small optional practice: no start date

Instead of beginning a plan on a fixed day:

1. Change one small thing today, without fanfare.
2. Do not announce it to yourself or anyone else.
3. Keep everything else the same.

If there is no dramatic start, there is no dramatic night before. The last supper only happens when something is ending.

When it might be more than a pattern. If the cycle of restricting and then eating large amounts happens frequently and feels out of control, it may be binge-eating disorder or another eating disorder. Talk to a doctor, especially if the episodes cause significant distress [6]. In the UK, Beat’s helpline for England is 0808 801 0677 [7]. In the US, call or text 988 if you are in crisis [6]. This article is general education, not treatment.

For more on the broader cycle that the last supper feeds into, see the restrict-binge cycle explained.