There cant be many people that dont know fruit is better for you than sweets but if it was a simple as "just swapping" no one would have a weight problem!
This isn't strictly true though.
Fruit has greater health benefits overall than sweets (obvs, there are no nutrients at all in sweets) but sugar wise, there isnt a huge amount of difference. Of the 5 a day advice, only 2 (max) of those 5 portions are supposed to be fruit because of the high sugar content. A lot of people don't know that OJ has as much sugar in it as coke and feel virtuous when they swap but without realising they are doing the same damage to their bodies metabolism and weight wise.
A breakfast of porridge, a banana and a glass of orange juice or a fruit smoothie is seen as a healthy choice but has a similar impact on the body to junk food insulin/metabolsim/weight wise due to high carb content.
I don't have the science at hand at the moment but sugar is the bad guy in this, not fat. Weight gain isn't caused by eating too much fat. Unless that fat is also consumed alongside a high carb intake because the body prioritises using carbs over fat as fuel because it's 'easier'. Weight gain is caused by insulin spikes as a result of high carb intake.
A lot of people don't know, understand or realise that all carbs are converted into glucose by the body to be utilised as fuel. And a lot of people don't realise that glucose is just sugar.
We have been pushed a low fat (eating fat makes you fat) and, therefore, high sugar, diet since the birth of the diet industry in, what?, the 60s. 'Healthy' options in supermarkets have the fat removed and replaced with sugar/sweeteners and thickeners. And yet we've never been fatter. Why?
An anecdote...
My ex husband eats low fat everything. He only eats lean cuts of meat, he only eats 0% fat yoghurt, salad dressings, he uses 'low fat' spray oils rather than fat for cooking etc. If fat were the issue, he'd be slim. But he's not slim, or even a 'normal' size. He's obese and he has T2 diabetes and horrendous sugar/carb cravings. He's always been frustrated by his weight because he follows the low fat guidance to the letter.
I used to be similar. Three stone overweight with the associated health problems. Always restricting my calorie intake to 1200 cals, never understanding why cals in/out worked for me for a short time but then stopped.
I moved to a low carb way of eating a few months ago. My calorie intake has increased. It's not a 'restrictive' diet in that sense. I now consume around 1600+ calories a day I only eat 'real' food. I eat pork belly, real butter, cream and fry (rather than grill) my food in lard alongside salad and leafy green veg etc. I've turned the food pyramid on its head and, yet, I've lost all sweet/carb cravings and have lost weight as well as improving overall health. People who talk of cravings and addiction, yes, it requires will power fornthebfirst few days but I can sit in a room with people eating cakes, sweets and chocolate and whereas I'd previously have been dipping in for extras when no one was looking, I have no desire to eat it at all now.
The carb/sugar cravings aren't inevitable. They can be controlled and even stopped.
But still the eatwell plate promotes high carb and low fat intake. Why?