Why hadn't I taken more notice of the recommendation on the Delicious Athens walking tour website? What could be clearer than "eat a light breakfast because you'll be sampling lots of culinary delicacies during your three-hour ramble around the heart of Greece's capital"?
But we'd been lulled into a false sense of security with our first two stops. After meeting at 10am outside the Archea Agora archaeological site (a five-minute walk from the Monastriki metro station), our group had sat down to enjoy a Greek coffee, then strolled on for five minutes to sample the traditional sesame seed bread ring Greeks calls koulouri.
This bakery, To Koulouri Tou Psiri, doesn't look impressive. "But this is the oldest and most famous koulouri bakery in all Athens," our guide Christina tells us. "It dates back to 1934, and has been making traditional Thessaloniki-style koulouri since 1965.
"They start baking here at 2am and deliver koulouri by scooters to street vendors all over the city."
Christina hands a koulouri to each of us but tells us not to eat more than a couple of mouthfuls: "One will keep you filled up for most of the day, and we don't want to ruin your appetite."
At Kafenio 111, on Ermou Street in the city's antiques district, we'd been served a traditional coarsely ground coffee by a member of a family which has been roasting coffee on this spot since 1922. As we sip them, Christina explains how, to her, Greek coffee represents all that is best about Greek cuisine, and Greek culture generally.
Making coffee, Greek-style, requires patience and attention, she says. Take your eye off the traditional briki coffee pot over the stove and you may well spoil the coffee. And it is a drink that is meant to be savoured, with friends or family. Sipped slowly – an excuse to continue long conversations.
"This is what I love about Greek cuisine," Christina says. "Food is a need, of course. But Greek food is about satisfying other needs – the need to share time with people and the need to sit down with them over something made with love as much as satisfying hunger."
Christina's boss, Tina Kyrlakis, began the Delicious Athens walking tour in 2012 "because I love exploring different places to eat". Since then, her company – Alternative Athens – has added other boutique walking tours to its list. But Delicious Athens remains the most popular – particularly with Australians.
The thing about a good culinary walking tour is that it gives you a truly intimate appreciation of how the locals in a city really live. Where they buy their ingredients; how far they are prepared to travel for something that is the best of its kind; what kind of restaurants they like to eat in away from the tourist trail.
However, our third stop this morning shows how much Greek cuisine is changing. Pantopoleio, on Ifestou Street in the famous flea market, only opened in January 2015. It's a very upmarket delicatessen selling a wide range of Greek wines, beers, olive oils, vinegars, cheeses – all from boutique operators spread over the whole country.
"We don't have a very complicated cuisine," Christina says. "We concentrate on the quality of our produce. But we have been very bad at promoting how good our produce is."
For the next 45 minutes, we are given a gourmet introduction to emerging Greek food trends. Christina pours two types of extra virgin olive oil (one from Crete and the other from the Peloponnese peninsula) and asks us to dip "monastery-style bread" into each one to taste the difference. The feta cheese we taste is a blend of 70 per cent sheep's milk and 30 per cent goat's milk (most feta, apparently, is 100 per cent sheep's milk), and we try it with various additions – fresh oregano from Sparta, a vinegar made from sour cherries, a thick tomato paste from Santorini, and a small glass of Nykleri white wine also from Santorini.
This is where I begin to regret breakfast.
But now we're on the move again to Thessaloniki at Psiri, which Christina describes as "a classic Greek pie joint", celebrated for both its savoury and sweet versions of bougatsa – wafer-thin layers of filo pastry filled with either minced meat or custard cream. The man making them has been doing it for 17 years and demonstrates the art form, throwing and spinning each disc of filo like a piece of street theatre.
Our next stop is visually stunning. Miran Kourounlian arrived in Athens in 1922 from Armenia and established one of Greece's first cured meat businesses. Today his showcase shop, Miran, is an Athens institution where red-aproned staff sell scores of different types of pastourma (cured meats, mainly beef and camel), soutzouki (a dry spicy sausage) and cheeses.
We join the locals sitting down at heavy wooden tables and sample the treats before we buy (the platter we try includes slivers of dried water buffalo and a very young, rubbery goat's cheese).
Fortunately, there's a pause before our final eating stop, because now it is time for Christina to take us for a tour of Athens' central markets. First we see the vegetable market, then the area where locals buy their spices and their nuts.
But nothing compares to Athens fish market. Both it and the meat market are housed in neighbouring 18th century halls. The meat market has its oddities (the whole pig's heads hanging above certain stalls for example), but it is sedate compared with the sheer noise and drama of the fishmongers as they tout for business.
Now, Christina insists, it is time to try a couple of Greece's most famous street foods. At Krinos, one of the city's best donut shops, we tuck into crisp, fluffy balls that have been quick-fried in cotton seed oil, then smeared with honey and cinnamon.
But the best is saved until last. Souvlaki Kosta has been operating from a simple hole in the wall since 1946, when the father of the present owner founded the business.
Nothing has changed in the souvlaki formula since then. The same pork chunks grilled on kebabs, then mixed with diced tomato, various herbs and served in a roll of thick doughy bread.
We sit and eat them on the street, along with scores of lunching Athenians. Note to self: better skip dinner.
Qantas and partner Emirates are among the airlines with regular flights between Sydney-Melbourne and Athens.
Alternative Athens operates 11 tours or experiences, including the Delicious Athens Food Walk, street art walk, Greek mythology tour, "cool shopping" walk, Gay and Lesbian tour, two adventures for children and families and the chance to experience home-cooked meals.
The Delicious Athens tour costs $70 a person, runs Monday to Saturday and includes all tastings. See alternative-athens.com.
Steve Meacham travelled at his own expense.