Starting a Diet: The Factors That Really Matter

You probably know the feeling. You start motivated, change the way you eat, move more — and it works. Until suddenly it seems to stop working. The scales stall, your energy drops and you start wondering what you are doing wrong.

Most of the time, you are not doing anything wrong. Many diet plans simply gloss over a few factors that matter more than they first appear. Not complicated biochemistry, but practical principles that can make a real difference — especially if you are starting, or starting again, after 40.

How large should your calorie deficit really be?

You do need a calorie deficit to lose weight. But the classic rule of “500 kcal less per day” is too rigid as a starting point for many women. For a smaller or less active woman, 500 kcal can already represent a 25 to 30% deficit — large enough to make the diet unnecessarily difficult to sustain.

A more useful starting point is around 10 to 20% below your maintenance needs. For many women, that works out at roughly 300 to 500 kcal per day — but what matters is how that figure relates to your individual needs, not the number on its own.

How quickly should you lose weight? A practical guideline is around 0.25 to 0.75% of your body weight per week. Faster is not automatically better: a larger deficit can increase hunger and fatigue and raise the risk of losing muscle mass without improving long-term results.

One thing many women find reassuring: a scale that does not move for one or two weeks tells you very little. Water retention, your menstrual cycle, salt intake and recovery after training can all affect your weight in the short term. Look at the trend over at least three to four weeks.

Sustainability over speed

Your body does not view weight loss as a victory. It responds to a period of lower energy intake by adapting. That adaptation is neither dramatic nor irreversible, but it is measurable: over time, the same eating pattern may result in slightly lower energy expenditure, partly because your body is lighter and requires less energy.

That is not a “damaged metabolism”. It is a normal physiological response, and the extent varies from person to person. It is also why an approach you can sustain usually works better than one that delivers fast results but becomes impossible to follow after six weeks.

So the question is not only “Does this diet work?” but also “Could I still follow this in six months?” If the answer is no, a plan that looks slightly less perfect on paper but fits your real life is often the better choice.

Protein: the most underrated factor

If there is one macronutrient many women do not eat enough of while dieting, it is protein. That matters because protein is especially important when you want to preserve muscle mass while losing weight.

For women aged 40 to 55, a practical target is around 1.2 to 1.6 g of protein per kilogram of body weight per day. Ideally, spread this across three to four eating occasions, with roughly 25 to 35 g of protein per main meal. That is more than many women are used to eating, but it can make a noticeable difference to satiety and to how well you maintain muscle mass.

Protein can also help you manage hunger, which can make a calorie deficit easier to sustain. Meat, fish, eggs, Greek yoghurt, quark or cottage cheese, and pulses can all contribute — choose the foods that suit you and spread them across the day.

Carbohydrates: not the enemy, but still a choice

Carbohydrates are often blamed for weight gain, but that is too simplistic. Weight gain develops through a sustained energy surplus, not because of carbohydrates themselves. Highly processed carbohydrate-rich foods such as biscuits, white bread and soft drinks can make that surplus easier to reach because they often provide relatively little satiety for the calories they contain. That is more a question of food quality than a problem with carbohydrates as a whole.

For most women in our audience, strict carbohydrate cycling — eating more carbohydrates on training days and less on rest days — is unnecessary. For walking or light resistance training, a balanced meal is usually enough. Only for intense training sessions lasting 60 minutes or longer can it be useful to eat around 20 to 40 g of carbohydrates beforehand — for example fruit with yoghurt, a small portion of oats or a slice of wholegrain bread. After training, a normal meal containing protein and carbohydrates is enough in most cases.

Carbohydrates do not need to disappear on rest days either. If you are less hungry and less active, your portion of rice, pasta or potatoes can simply be a little smaller. Vegetables, fruit and pulses still have a place on rest days too. The focus is on quality and portion size, not elimination.

Resistance training: essential if you want to lose weight sustainably

When you create a calorie deficit without resistance training, you may lose muscle mass as well as fat. Preserving muscle is valuable for strength, function and long-term weight management, so it is something worth actively protecting while you lose weight.

The basics are simpler than many people think. Two full-body resistance-training sessions per week, with at least 48 hours of recovery for the same muscle groups, are a very good starting point. You do not need a complicated programme. Cover the major movement patterns: a squat or knee bend, hip extension, pushing, pulling and stepping. Machines, free weights, resistance bands and bodyweight exercises can all work, as long as the resistance is challenging enough to create a genuine training stimulus.

As a practical starting point, aim for 1 to 3 sets per exercise and 8 to 15 repetitions, stopping while you could still perform around 2 to 3 technically sound repetitions. Gradually increase the resistance once it becomes too easy. Consistency and progression matter more than having the “perfect” programme.

What really changes after 40 — and what does not

Many women notice that losing weight after 40 feels different from before. That can be true, but your metabolism does not suddenly “switch off”. What changes are mainly three factors that partly overlap.

First, without targeted resistance training, muscle mass gradually declines with age. Less muscle can mean slightly lower energy expenditure — not a dramatic change, but one that can become noticeable over the years.

Second, the decline in oestrogen around menopause is associated with a change in fat distribution, with fat more often stored around the abdomen and less around the hips and thighs. That can change how your body looks, but it does not make fat loss impossible.

Third, indirect factors such as poorer sleep, more stress or joint discomfort can affect eating behaviour, recovery from training and spontaneous daily movement. These are real obstacles, but many of them can also be influenced.

The main message is that losing weight remains physiologically possible after 40 and during menopause. The calorie deficit you need may be slightly smaller and progress may feel slower, but the basic mechanisms still work. Resistance training, enough protein and an approach you can maintain do not become less important at this stage of life — they become even more valuable.