Actually no, that's not a "fact". It's flat out false. Unless your "meal" consists of 2 double cheeseburgers from mcdonalds every night.
Bag of frozen broccoli flourets = $2 and will last 2 meals.
Can of green beans = $1
3 .5lb pork chops ~= $6
4lbs of chicken drumsticks - $8 (even cheaper when on sale)
1 meal consisting of some protein and veggies will run you about $3 - $4 bucks after you add in a little bit of seasoning and olive oil or butter.
Yeah, I eat pretty cheaply by cooking at home. For example, I buy big bags of frozen salmon filets from Sam's Club. Price per filet works out to $2 each. Local grocery store has 10 for $10 for bagged frozen veggies all the time (or bulk frozen bags from Costco), and I only use half of one of those bags for a lunch meal for myself. A 20-pound bag of rice is $20 from the local ethnic stores (jasmine, basmati, etc.). 2 cups of white rice is about a pound, so 1 cup of rice is 50 cents. RideFree's bread recipe costs under a quarter per loaf. So say $3.25 for meal consisting of a salmon filet, jasmine rice, a cup of steamed broccoli, and a slice of fresh bread (we'll be generous & count the slice for loaf pricing, haha). A Big Mac (sandwich only) is $3.99. Bonus, I can cook the filet, rice, and broccoli in my Instant Pot & the bread in my bread machine, so actual work is minimal.
Cooking fresh, healthy meals is typically only more expensive is you buy pre-packaged food, buy fancy ingredients, or are comparing it to rock-bottom-priced fast food. But for items like the 4 for $4 meal at Wendy's, I'd typically rather have the salmon/rice/broccoli/toast meal (unless it's a Whopper, because I have a weakness for those lol). The
convenience is what costs you money: buying buffet food from Whole Foods, frozen healthy dinners, online stuff like Blue Apron, etc. Or buying high-end ingredients like filet mignon or what have you. I mean, Texas Roadhouse charges $17.99 for a 12-ounce NY strip steak. I can get the same thing for half-price at the grocery store & sous vide it up into a better meal than they can do. I'm not knocking going out to eat, but if you're really serious about
eating healthy on a budget, you can basically eat like a king without spending a fortune if you're willing to make a menu, go shopping, and cook. Pinterest has a zillion delicious recipes available for free. And if you're willing & able to invest in cooking appliances like electronic pressure cookers, you can cut the actual effort required down quite a bit by automating it.
Digging even further into it, you can save money by buying & cooking in bulk. Lately I've been doing batches of stuff & freezing it for later use, even desserts like chocolate-chip cookie dough, peanut butter cookie dough, cinnamon rolls, brownie batter (in cheap disposable foil containers), etc. I go through a lot of chicken breast & try to only buy it on sale - it goes from $22 every other week for a big pack of fresh BSCB to $12 on sale. Vacuum-seal those puppies up for sous vide or other cooking methods. We have the technology (appliances) & the education (the Internet) to make it happen, so it mostly boils down to whether or not an individual is willing to put in the work to make it happen. It's a lot easier just to do take-out or drive-through meals, and you're guaranteed a tasty, hot meal with zero effort, which is awesome. The Dollar menu & other super-budget menu items will always trump cost for food because they can pump those out in ridiculously large bulk quantities. But if you're willing to cook, you can cook reasonably healthy & delicious meals on a budget, no problem.