Why Do I Keep Losing Weight and Gaining It Back?

Weight regain after dieting is not a failure of willpower. It is the predictable result of an approach that treats the symptom - weight gain - without addressing the habits, beliefs and triggers that caused it. The cycle has a name: yo-yo dieting. And there is a way out of it.

I'm Caroline Tyrwhitt, a food relationship coach and author of The Mindset Diet. I help people escape the dieting cycle by understanding the psychology behind their eating. I have been through this cycle myself - many times.

What is yo-yo dieting?

Yo-yo dieting is the cycle of restricting food, losing weight, returning to previous habits and regaining it - often repeatedly over months or years. The name reflects the pattern: up, down, up, down.

If you have found yourself losing weight on a diet and then gradually gaining it back again, you are not alone and you are not doing it wrong. The approach itself is the problem.

At one end of the cycle, you follow rules, restrict what you eat and put all your focus into losing weight. At the other end, you give in to exhaustion, rebel against the diet or promise yourself you will start again tomorrow. Neither side feels sustainable - because it is not.

Over time, that swing becomes emotional as well as physical. Hope, deprivation, discipline, frustration, guilt, disappointment - on repeat.

Why do diets stop working?

Going on a diet is, by definition, temporary. Most diets focus on what to eat, what to avoid, and how quickly you can change your body. They rarely ask how you got there in the first place, or what happens after the diet ends.

So when the diet stops, life goes back to normal. And with it, your old patterns come back too.

As I explore in The Mindset Diet, diets tend to treat the symptom rather than the underlying cause - your habits, beliefs, environment and relationship with food. Diets teach you how to restrict. They do not teach you how to live.

My experience of the dieting cycle

I have lost count of how many times I went round that cycle.

When I was younger, dieting felt normal. My mum dieted, so I dieted. We ate different meals to the rest of the family until we eventually went back to eating normally again. I tried every fad going - grapefruit, the F-plan, Cambridge.

As I got older, life became busier. Teaching, long hours, pressure to perform. I did not have the time or energy to keep going on a diet in the same way, and tomorrow kept getting further away.

I would try dieting for a couple of weeks, lose some weight, and then put it back on as soon as I returned to my usual routine. Eating out, grabbing food on the go, rewarding myself with treats, unwinding with a glass of wine.

Each time, I told myself I just needed to try harder. Be more disciplined. Have more willpower. I became disillusioned. I did not want to keep depriving myself. But I also did not know another way.

It felt like an either/or choice: focus on my life and ignore my weight, or put my life on hold to control it.

What actually drives weight regain?

When you look beneath the surface, weight regain is not random. Research points to a range of contributing factors - hormonal changes triggered by calorie restriction, genetic predisposition to weight gain, and set point theory: the weight range the body wants to maintain, which can shift upward over time. Evidence also suggests that dieting at one point in time predicts weight gain at a later point.

What is consistent across all of this is that our eating and our weight are driven by patterns. Three in particular:

Habits

After a diet ends, we return to familiar routines - the same shopping habits, the same ways of eating out, the same coping mechanisms. That neural wiring is strong. It pulls us back, especially when we have been treating the diet as a temporary state rather than a genuine change in how we live.

Triggers

We do not eat only when we are hungry. We eat because we are tired, stressed, overwhelmed, or simply because food is there. Triggers set off habits. If those triggers have not been identified and addressed, the old habits come back quickly.

Beliefs

The stories we carry shape our behaviour and our identity:

• "I have no willpower."

• "I can not keep weight off."

• "I have failed again."

If the inner work of changing those beliefs is not done, they will continue to shape the outcome.

The failure is not a lack of discipline. It is the mind and body doing exactly what they were designed to do.

Why does all-or-nothing thinking make it worse?

Dieting creates a black-and-white mindset. You are either on the diet or off it. Being good or being bad. In control or out of control.

When something disrupts that perfection - a busy week, a holiday, a stressful day - it is easy to feel like you have failed. That feeling of failure often triggers giving up entirely, which swings the pendulum back to old habits.

The problem is not that you cannot stick to the plan. It is that the plan was not designed to achieve a lasting result.

How do you break the yo-yo dieting cycle?

For me, the shift came when I stopped thinking about going on a diet and started thinking about changing my diet. Not through restriction, but through investigation - understanding what had caused me to gain weight in the first place.

Instead of asking what to cut out, I began to notice what was actually going on. I observed my habits, my triggers, my patterns - without judgement. From that awareness, I started making small changes that worked for me rather than following someone else's rules.

Three areas that made a real difference:

• How I lived - the routines, the environment, the situations that triggered eating

• How I thought - the beliefs, the inner critic, the all-or-nothing thinking

• How I nourished myself - moving from restriction to genuine care for my body

How do you rebuild trust in yourself after yo-yo dieting?

One of the less-discussed impacts of yo-yo dieting is the loss of trust - in your body, in your choices and in yourself. After years of following external rules, it can feel impossible to know what you actually need.

Rebuilding that trust does not start with more control. It starts with awareness and self-compassion. Not as a soft alternative to change, but as the foundation that makes sustainable change possible.

Frequently asked questions

Is yo-yo dieting bad for you?

Yes, in several ways. Repeated cycles of weight loss and regain can make it progressively harder to lose weight, due to metabolic adaptation and shifts in the body's set point. It also takes a significant emotional toll - the cycle of hope, restriction, perceived failure and guilt compounds over time.

Why do I regain weight so quickly after a diet?

The body has strong regulatory mechanisms designed to return to a stable weight. When calorie intake drops significantly, hormones shift to increase appetite and reduce energy expenditure. Once normal eating resumes, those mechanisms push weight back up - often to slightly above where it started.

How do I stop the cycle of losing and regaining weight?

The most effective approach is to move away from dieting as a temporary intervention and toward understanding your relationship with food - the habits, triggers and beliefs that drive your eating. Small sustainable changes, made from a place of curiosity rather than restriction, are more likely to produce lasting results than any short-term plan.

Does willpower have anything to do with weight regain?

Very little. Weight regain is largely driven by physiological and psychological patterns rather than a lack of self-discipline. The belief that willpower is the missing ingredient is itself one of the beliefs that keeps people stuck in the cycle.

Ready to stop letting the cycle repeat?

I run a one-hour workshop where I show you how changing the way you think about weight loss and dieting can help you achieve it with more ease - and sustain it this time. We look at how to align your eating with your purpose, your values and your identity.

Register here: https://mindsettips.co.uk/workshop

You can also join my free community The Mindset Diet Revolution on Skool, where I share mindset tips to support you on this journey: https://www.skool.com/the-mindset-diet-revolution-8621/about

Caroline Tyrwhitt is a food relationship coach and author of The Mindset Diet. She is the founder and director of Free to Be NLP (freetobenlp.co.uk).