Trying to lose weight - Sports drink and food during ride

I'm no expert but I'm going to suggest that anything less than an hour* doesn't need any extra fuel past hydration.

*I'd extend that up to 2 hours if taking it easy.

I would agree, 3-4 hour rides upwards you might need something if you're cycling quite hard.

on your 2-3 hr rides you should be aiming at Z2, a good way to check you're in zone is the talk test. Casically if you can talk out loud in complete sentences while you are riding the pace is low enough.

if this were correct it obviously would be impossible to lose weight

clearly it isn't

As a general rule of thumb, if you are starving at the end of a 3hr ride then you have got your calorie intake badly wrong on and off the bike.

I ride 13-15hrs per week with 3 x 4hr rides. At the end of a long ride I have some chocolate milk or a yoghurt and maybe a small handful of salted peanuts. That is all I need before having a proper meal about an hour or so after the ride.

Whether you should fuel your rides by taking calories intra workout or not will depend largely on when those rides take place during the day, what your eating habits are throughout the day, and how long you have already been in a state of caloric deficit. To lose 3 stones should take you at least a year to a year and a half of a sensible (300-500 kcal per day), but strictly everyday calorie restriction. That's a long time, and once your body fat tissue starts disappearing your body will kick off all sorts of adaptations to prevent any further loss. One of those adaptations is reducing your spontaneous physical activity such as gesturing throughout the day and also reducing the willingness to undertake planned physical activity as being in a prolonged caloric deficit affects negatively muscle recovery and central nervous system so we feel less keen to do things which cost us energy. This can be amplified further by doing sport especially endurance type sports such as running, cycling, swimming are known to cause that.

Fuelling simple carbs intra-workout have been found to help prevent that to a degree, especially during workouts taking longer than 2 hours. No need to take in much, 40g per hour is enough. Just keep in mind to include those calories in your daily calorie in\out balance. Just monitor your vitality levels throughout the day and if you find it drops, you can try fuelling intra-workout and see if it lifts your energy levels up. I do this by measuring the cadence when I walk. When I am eating well this will be 124-126 steps per minute, but after 6-8 weeks of dieting for weight loss I observe this to spontaneously drop to 115-118. This tells me it is time to do a 3-4 weeks diet break to come out of the calorie deficit.

Now, if your rides take place in the afternoon and you tend to eat regular, equally spaced meals throughout the day, you don't need to fuel intra-workout, but if you ride very early in the morning with no time to eat breakfast at least 2 hours before the ride, it is worth eating some source of simple carbs including fructose just before the ride or on the bike to top up liver glycogen stores which can be depleted after the night, especially if your last meal the previous day was at the most desirable time - 6-7pm. Liver glycogen is a source of fuel for the brain, and if the levels are already low and you deplete them further, your brain will likely make you crave simple sugars post ride, which may lead to overeating. If you ride your longer ride also very early in the morning, fuelling on the bike will be even more important, because otherwise you will be finishing your ride with a large caloric deficit which will make you find curbing appetite later in the day much harder.

Lastly, it would be beneficial to include some resistance type training in your training plan. Either doing weights, or a simple home workout with your own body weight, or kettlebells, or else calisthenics. Best a mix of all. Short, twice a week, to muscle failure. It will help to minimise skeletal muscle loss from your entire body during the weight reduction period. You don't mention your age, but this is especially important if you are past your 40 years, and paramount past 50 when sarcopenia starts accelerating.

You are right and those compensations take place, but can be minimised by eating a high quality, dietary fibre and nutrient rich, high carb / low fat diet with a sensible caloric deficit on one hand and managing daily stress levels by ensuring good quality sleep, post workout recovery and avoiding overtraining and excessive use of stimulants such as caffeine. People are struggling to lose weight not because those compensations make it impossible, but because they listen to the advice of people unqualified to give it and live in a highly obesogenic environment at the same time. The human body evolved to be very efficient at gaining fat tissue and preventing losing it because it was once crucial for survival, and has powerful tools to succeed at it, but modern food industry is exploiting every one of those primal mechanisms to ensure we keep eating mostly their junk food.

Feeling an irresistible urge to eat the whole contents of the fridge post ride is typical to those aiming at very rapid weight loss and who starve themselves throughout the entire day eating very little, then workout later in the afternoon with either no or very little fuelling on the bike, possibly also only drinking plain water, so not hydrating properly. When they return home they are indeed starved, dehydrated (thirst causes cravings for sugary foods), and that at the time of the day when ghrelin are naturally highest - late in the afternoon / into the evening, so they end up bogging in.. then feeling guilty in the morning, so restrict eating again throughout the day to try to balance the excess calories out, then can't resist hunger again and overeat again and keep on bouncing between one extreme and the other.