Try pointing out the marathon runners who consume processed sugar often in a race......if it was ‘bad’ would atheletes be doing that.
This is what happens when people listen to media crap, they hear the headline and dont bother to learn the science behind it.
Sugar (whether processed, in fruits, fructose, glucose, brown rice syrup etc etc) is just sugar, it’s a carb that can be ultilised by the body very quickly as fuel - nothing more nothing less.
Your bother in law (like loads of people to be fair) has seen the media stating ‘processed sugar is the reason for the obesity problems’ - now this is true IMO.
However, people assume that it’s the sugar that’s causing the problem, it’s not, it’s the fact most people consume far too much and don’t use it as fuel (which means it gets stored as fat). It’s easier to over comsume processed sugar (especially in a drink) without fibre and fat present as it’s quickly absorbed, causes a spike in insulin followed by a crash leading to a desire to eat more (there’s also evidence of endorphin release from sugar similar to that from drugs).
However, the actual sugar causes no issue itself.
Fruit is stupidly demonised by people at the moment - no one ever went to fat camp for eating too many strawberries did they - ffs
Fruit (as you point out) typically contains fibre and a host of other food stuff. I personally use a fruit smoothie as a pre work out fuel.
You are correct, your brother in law is wrong. However, for most overweight people cutting out processed sugar is probably the second or third best change they can make to their nutrition (after tracking and potentially increasing protein), not because of the sugar per se, but because it will assist them to consume less overall calories (as we know a deficit is needed for weight loss) and forces them to eat more whole foods (processed sugar is in loads of convenience foods).
