Tongue posture is only one part of the equation. Nose breathing, proper swallowing, and chewing are also important for improving one's appearance and health. The airway is not only affected by the maxilla but also the mandible. A lot of the appliances used today are useless long-term because they do not enforce proper oral habits. My current dentist also argues that appliances like DNA, Homeoblock, Agga, and the likes which lock the upper jaw in place are detrimental because they block proper flows of cerebrospinal fluid. A lot of dentists using these appliances don't even know what they're doing.

Posted by: @ancoratu

Tongue posture is only one part of the equation. Nose breathing, proper swallowing, and chewing are also important for improving one's appearance and health. The airway is not only affected by the maxilla but also the mandible. A lot of the appliances used today are useless long-term because they do not enforce proper oral habits. My current dentist also argues that appliances like DNA, Homeoblock, Agga, and the likes which lock the upper jaw in place are detrimental because they block proper flows of cerebrospinal fluid. A lot of dentists using these appliances don't even know what they're doing.

Very true.

Tongue posture aka "soft mewing i guess?" is, quite literally, the result of proper nose breathing and body posture. 

3 sessions of cardio and 2 of weightlifting per week Will push your tongue and mandible forward naturally. 

3-4 litres of water a day Will make na huge difference aswell.

I did a treatment with an appliance very similar to a DNA and it really didnt work at all, it actually Gave me an Open bite. Im 28 years old.

Why? I was a smoker, overweight, scoliosis, lots of work, stress, etc.

Mewing as an exercice doesnt work and ONLY causes assymetries. Mewing is something you will naturally achieve when youre healthy and regularly do cardio/weightlifting, drink lots of water during the day.

If you see no change and you have no eyebags you wont Change your looks too much.

IF you have eye bags you may be able to improve and upswing the maxilla by being healthy. 

@Roflcopters

I did the DNA appliance for like 8 months, and ultimately it did not fix anything for me. My dentist was so excited about what this appliance could do for me I couldn't really tell her that it barely did anything for my health issues. I agree that living a healthier life will make you healthier but some people with craniofacial problems can't even exercise because it makes things worse for them. In my case, my lower jaw is malpositioned in a deep bite malocclusion. This has led to TMJ problems which in turn led to neck problems, neurological problems, migraines, bad sleep, anxiety/depression, scoliosis.  As I wait to travel to see a real TMJ specialist I've been wearing a SODIS apf functional activator that allows me to sleep better because it pushes my mandible forward. It has also removed some of the extreme incisor tipping from the DNA appliance. The functional activator has trained my tongue to be on the roof at all times, to breathe through my nose, and to swallow correctly. Furthermore, It has achieved forward growth as well as palate expansion such that my tongue fits very comfortably on the roof of my mouth.

https://functionalactivator.com/

Not an advertisement but if someone's looking for an appliance or device that you can wear at home to improve oral habits this is your best bet. 

Why does drinking 4 litres of water help? Also when weightlifting and doing cardio should we breathe through the nose? I have under eye bags so I definitely need to fix my maxilla but believe as an adult its very difficult even with a perfectly healthy lifestyle 

Posted by: @harrykanemaxilla

I am 19 years old are started mewing at 16. So 3.5 years I have been mewing yet I haven’t seen any change. Occasionally I think my cheekbones look better however I think its placebo. I do believe mewing works but only if its done when you are a baby. After age 12 you wont get any changes. Maybe appliences can help but natural mewing with teeth in contact has done nothing to move my maxilla.

false,
ur technique is off

Posted by: @adam

Posted by: @harrykanemaxilla

I am 19 years old are started mewing at 16. So 3.5 years I have been mewing yet I haven’t seen any change. Occasionally I think my cheekbones look better however I think its placebo. I do believe mewing works but only if its done when you are a baby. After age 12 you wont get any changes. Maybe appliences can help but natural mewing with teeth in contact has done nothing to move my maxilla.

false,
ur technique is off

The way I see mewing is that its the natural posture of the body and doing mewing from the start of life or a very early young age will lead to a well placed maxilla in adulthood too. Everyone is born with a perfect maxilla unless there are very rare circumstances. However most people develop bad mouth breathing habits and/or postures during their childhood and continue this until adulthood. As a result their maxillas grow incorrectly and they develop CFD. Once they turn age 12 and over, the maxilla in the CFD person has been hugely setback and to get the maxilla back on track is going to be extremely difficult as the person will have to reshape bone! And the reshaping of the maxilla will be compression as the shape would be changing from long to shorter. There isn’t much any empty space so the maxilla would be compressing into itself upward with space to grow forward. Whereas when the CFD developed for the person, it was a tension force and there was empty space for the maxilla to grow into as the tongue was off the palate and the mandible hanging down. Even with perfect posture, the person above age 12 and especially over 18 years old will have strong bones that are stubbornly set in place for life. I personally believe CFD cannot be fixed even as an adult as bones are very strong. Mewing is a CFD preventative practice not a cure in my opinion. However I hope to be wrong.

Posted by: @harrykanemaxilla

Posted by: @adam

Posted by: @harrykanemaxilla

I am 19 years old are started mewing at 16. So 3.5 years I have been mewing yet I haven’t seen any change. Occasionally I think my cheekbones look better however I think its placebo. I do believe mewing works but only if its done when you are a baby. After age 12 you wont get any changes. Maybe appliences can help but natural mewing with teeth in contact has done nothing to move my maxilla.

false,
ur technique is off

The way I see mewing is that its the natural posture of the body and doing mewing from the start of life or a very early young age will lead to a well placed maxilla in adulthood too. Everyone is born with a perfect maxilla unless there are very rare circumstances. However most people develop bad mouth breathing habits and/or postures during their childhood and continue this until adulthood. As a result their maxillas grow incorrectly and they develop CFD. Once they turn age 12 and over, the maxilla in the CFD person has been hugely setback and to get the maxilla back on track is going to be extremely difficult as the person will have to reshape bone! And the reshaping of the maxilla will be compression as the shape would be changing from long to shorter. There isn’t much any empty space so the maxilla would be compressing into itself upward with space to grow forward. Whereas when the CFD developed for the person, it was a tension force and there was empty space for the maxilla to grow into as the tongue was off the palate and the mandible hanging down. Even with perfect posture, the person above age 12 and especially over 18 years old will have strong bones that are stubbornly set in place for life. I personally believe CFD cannot be fixed even as an adult as bones are very strong. Mewing is a CFD preventative practice not a cure in my opinion. However I hope to be wrong.

You are, just follow the evidence, there r a some ppl having results >20 yo, read their testimonials/threads (esp jamo and hassan), focus on technique, 1 hour a day is enough for starters (and u dont have to hard mew - tho it can feel like it if u place your tongue in the right place - just do it proper), u will get better at it once ur palate expands.
Back to your point: the truth is, mewing is in fact expanding the skull and straightening the spine so there is ample of space for maxilla to move forwards.