How to lose weight safely and keep it off
8 min read · Updated 2026-10-11 · FitCalc
Losing weight is governed by energy balance — eat less than you burn and weight falls. But how you create the deficit decides whether you keep muscle, whether you feel well, and whether the result survives contact with real life six months later. Slower, structured loss outperforms crash dieting on almost every measure that matters.
Why a moderate deficit wins
A deficit of roughly 10-20% below your maintenance calories is a common starting point. It is large enough to produce visible, motivating progress and small enough to preserve muscle, maintain training performance and stay tolerable socially.
Aggressive deficits produce faster scale movement but come with costs: more lean mass lost, more fatigue, and a higher chance of abandoning the plan. Because water weight shifts quickly, the first week's loss is usually not representative in either approach.
How fast is reasonable
A widely used guideline is around 0.5-1% of body weight per week. For a 90 kg person that is roughly 0.45-0.9 kg per week. People with more fat to lose can often sustain the faster end of that range; people already lean should move more slowly.
Weight also fluctuates daily with hydration, salt, food volume and hormonal cycles. Judge progress on a weekly average, not on individual mornings.
- Set a moderate deficit — around 10-20% below maintenance
- Aim for roughly 0.5-1% of body weight per week
- Keep protein high to protect lean mass
- Include resistance training at least twice a week
- Track weekly averages, not daily readings
Protect your muscle
When you lose weight, some of that loss can be lean tissue rather than fat. Two things sharply reduce that risk: eating enough protein and continuing to train with resistance. Doing both means a larger share of the weight lost comes from fat.
This matters beyond appearance. Lean mass supports metabolism, strength, bone density and daily function, particularly as you get older. Losing it to hit a lower number on the scale is a poor trade.
The habits that make it stick
Diets fail mainly through adherence, not through biology. Building the plan around foods you actually enjoy, with a realistic calorie target and some flexibility, works far better than a rigid list of 'allowed' foods. Fibre-rich and protein-rich foods help because they keep you full for fewer calories.
Self-monitoring is one of the most consistently supported behaviours in weight management. Weighing yourself regularly and keeping a loose record of intake makes drift visible early, when it is easy to correct.
When you reach your goal
The maintenance phase is where most weight is regained, because the approach that caused the loss is abandoned. The key is to keep the habits and raise calories gradually back to a new maintenance level, continuing to train and monitor.
Expect some physiological pushback: the body tends to defend against weight loss through increased appetite and reduced spontaneous movement. Anticipating this, rather than being surprised by it, is part of planning for the long term.
Run your own numbers
Free calculators that answer the “how much” version of this question. They run entirely in your browser — nothing you type is uploaded or stored.
Common questions
Do I need cardio to lose weight?
No, the deficit does the work. But cardio supports cardiovascular health and increases energy expenditure, which gives you more room in the calorie budget. Resistance training is more important for preserving muscle.
Why did my weight stop dropping?
Common causes are a smaller body needing fewer calories, reduced spontaneous activity, and looser tracking. Recalculate maintenance at your new weight and check your intake before cutting further.
FitCalc provides general information only and is not medical advice, diagnosis or treatment. Figures are illustrative and depend on your own circumstances. Always consult a qualified health professional about your situation. See our full disclaimer.