Weight loss is not just calories.

Most people are told to “eat less and move more.” In real life, your body adapts, which is why progress can feel different from week to week. I use three levers to explain what’s going on and what to focus on next.

1. Energy intake
2. Energy expenditure
3. Biological regulation

When weight loss slows, it’s usually because one lever needs more support. Here are the three levers I look at.

Lever One: Energy Intake

At its most basic level, weight loss requires a sustained negative energy balance. But reducing intake is not simply about willpower. Appetite is regulated through complex hormonal signalling involving:

• Ghrelin (hunger signalling)
• GLP-1 (satiety)
• Peptide YY
• Insulin
• Leptin

When weight decreases, hunger hormones rise and satiety hormones fall. The body actively resists further loss. This is why calorie restriction alone often works initially and then becomes progressively harder.

Modern pharmacotherapy, including GLP-1 receptor agonists such as semaglutide and tirzepatide, primarily acts on this lever by altering satiety and reward signalling in the brain. The result is not forced restriction, but reduced biological drive to eat. That distinction matters.

What this means for you

If hunger feels louder some weeks, that does not mean you are failing. It often means this lever needs more support.

Practical tips for this lever

1. Start meals with protein. It helps with fullness and makes portions easier to manage.

2. Plan your hardest time of day. For many people it’s late afternoon or evenings. Decide in advance what you will eat then.

3. Make eating more “boring” for a week. Keep meals simple and repeatable so you are not negotiating with cravings all day.

Lever Two: Energy Expenditure

Energy expenditure is often oversimplified as “exercise”. In reality, total daily energy expenditure consists of:

• Basal metabolic rate (BMR)
• Thermic effect of food
• Non-exercise activity thermogenesis (NEAT)
• Structured exercise

As weight falls, the body adapts by reducing resting energy expenditure - a phenomenon known as adaptive thermogenesis. In some individuals, this reduction exceeds what would be predicted by body mass alone. In other words, after weight loss, the body becomes more efficient.

Exercise remains important - not just for caloric burn, but for preserving lean mass, maintaining metabolic rate, improving insulin sensitivity, and reducing cardiometabolic risk. However, exercise alone rarely produces large sustained weight loss without concurrent appetite control.

What this means for you

If you are doing the same routine and getting slower results, it may be because your body is burning fewer calories than it did earlier.

Practical tips for this lever

1. Pick a daily movement baseline you can repeat, even on busy days. A consistent walk beats an intense workout you cannot sustain.

2. Add two short strength sessions per week if you can. The goal is to protect muscle and support your metabolism.

3. Use “NEAT” on purpose. Small things add up: take calls walking, add a short walk after meals, stand up more during the day.

Lever Three: Biological Regulation

This is the lever most often ignored. Body weight appears to be regulated around a defended range - sometimes described as a “set point” or settling point. Neural circuits within the hypothalamus integrate signals from adipose tissue, the gut, and circulating nutrients. When weight drops below the defended range:

• Hunger increases
• Energy expenditure decreases
• Food reward sensitivity rises
• Satiety signals weaken

These responses are not psychological weakness. They are coordinated survival mechanisms. This helps explain why long-term weight maintenance is biologically challenging. The body interprets sustained weight reduction as a threat to energy reserves.

Bariatric surgery and incretin-based medications appear to modify this regulatory system, at least while active treatment continues.

What this means for you

When results slow or cravings spike, it can be your body trying to pull you back to what feels “normal.” This is why steady routines matter so much.

Practical tips for this lever

1. Protect sleep for a week. Poor sleep makes hunger and cravings harder to manage.

2. Lower your “decision load.” Keep food choices simple and keep your weekly routine predictable.

3. Reduce stress where you can. Stress often shows up as more cravings and more impulsive choices, even when your plan is good.

Why One Lever Is Rarely Enough

Short-term diets often pull only the intake lever. Exercise-only strategies primarily pull the expenditure lever.

But if biological regulation remains unchanged, counter-regulatory mechanisms gradually reassert themselves.

The most durable weight loss approaches - whether surgical, pharmacological, or structured behavioural - influence appetite signalling and metabolic adaptation in addition to caloric balance.

A simple way to use this this week

Choose one lever as your main focus for seven days, and do one small action daily. Keep the other two steady. This is how you stay consistent without feeling like you need to restart every Monday.