It’s not entirely simple.
Very often just cust cutting calories works for only a short time until the person hits a plateau due to the body adjusting the metabolism to the new normal of less calories. Sometimes the weight-loss just goes much slower, but many people stop losing weight without further additional calorie restriction.
The “average” calories for a female is very often over-estimated too as it assumes a 30 year old gym-goer not a 50 year old sedent, I would say the average maintenance calories for a man is 2000 and for a woman is 1500, so a woman would need to cut to 1000 calories to lose 1 pound a week. Obviously if the person is very active and goes to the gym or runs then that average man can have 2,500 maintenance and that average woman can have 2,000 maintenance.
Intermittent fasting works well as long as you stick to a maximum of an 8 hour eating window to start with and no snacks and if you stick to eating real non-processed food. Over time you should aim to increase the fasting period so you are only eating in a 6 hour window, then a 4 hour window etc. Fasting can have quick results which helps people believe in it.
The reality is though that to lose significant weight a decent amount of activity (housework or gym classes or walking the dog - however you want) is needed. I know someone who lost quite a few stone over a couple of years by changing lunch to only tomato soup and walking for at least two hours each day (walked to work, walked home at lunchtime, walked back to work, walked home in the evening).
For me personally the best thing I did for my weight and my health was stop eating carbs for a while to get to the weight I wanted. No grains (rice, flour, sugar), no starchy veg (potato), no heavy fruit (apples, pears etc) - only berries, more protein and more fat. I stopped getting hungry and found it easy to not eat.
Fruit is full of fructose so the enemy of weight loss - the only good thing in fruit is vitamin c - so stick to strawberries & raspberries.
Eggs are almost the perfect food - they contain everything the human body needs with the only exception being no vitamin c.
The Japanese do not eat crazy amounts of rice despite what you might think - they don’t gorge on carbs, and they do eat a lot of fat (fish) and one of the best health foods they have often is Natto - which is great for the heart and circulatory system. Healthy japanese people see a massive down-grade to their health and weight when they move west to our diet.
Now I am the weight I want I exercise 3 times a week and am careful - I still avoid bread, sugar etc. where possible but don’t cry if friends want to go to pizzahut.
I do a one hour full-body workout that is hard (exercising arms, chest, legs etc all at the same time) and that only burns 300 calories which is about 3 chocolate hob nob biscuits. So a pizza undoes an entire weeks exercise for me.
So you need a lot of exercise to only think of weight-loss. One of the easiest factors for weight loss is that muscle burns more calories so build more muscle by exercising and eating more protein.
The healthiest diet is a mediterranean diet with more meat and without bread and pasta.