I also don't see people talking about when and what to eat. Yes, it matters.
"The heat of the day" is typically between 4-6pm. Do NOT try to eat your heaviest meal in the late afternoon/early evening - it will make you sick.
Eat your heavier meals early in the day, or late - like after 8-9pm, as the temps drop. This is when you get your protein, meat or main dish and sides.
In the heat of the day, eat lightly - a bit of fruit, or yogurt, half a sandwich or bowl of cereal - and drink.
If you're able to be indoors in front of a/c or a fan, drink water.
If you must be outdoors, drink electrolytes too - coconut water, Hoist, gatorade, poweraid, pedialyte, LiquidIV, DripDrop, etc - alternating with your water.
Eat a bit more salt in your food - chips, crackers, etc. with your meals.
Train yourself to keep a drink at your hand and sip at it all day long. Make it muscle memory, habit.
If sweet drinks will make you drink more, then drink sweet drinks. Sweet tea, fruit juice in your water, etc.
Take things slow, and plan to do more in early morning or late at night, and rest in the heat of the day.
Adjust your clothing but also adjust the rhythm of your life. Adopt the habits of folk who live where it's dangerously hot. It's not quirks of culture - it's survival.