Since commercial juices are pasteurized in the USA, it destroys many vitamins including C. Then they add synthetic ones to it.

http://en.wikipedia.org/wiki/Flash_pasteurization

Flash pasteurization, also called "High Temperature Short Time" processing (HTST), is a method of heat pasteurization of perishable beverages like fruit and vegetable juices, beer, and some dairy products. Compared to other pasteurization processes, it maintains color and flavor better, but some cheeses were found to have varying responses to the process.[1]

It is done prior to filling into containers in order to kill spoilage microorganisms, to make the products safer and extend their shelf life. Flash pasteurization must be used in conjunction with sterile fill technology (similar to aseptic processing) and therefore has the risk of post-pasteurization contamination if hygiene standards are not rigorously enforced.[2] Flash pasteurization is often used for the pasteurization of bulk products such as keg beer, milk, and kosher wines.

The liquid moves in a controlled, continuous flow while subjected to temperatures of 71.5 °C (160 °F) to 74 °C (165 °F), for about 15 to 30 seconds.

Flash pasteurization is widely used for fruit juices. Flash pasteurization was first developed by Tropicana Products, which has used the method since the 1950s.[3] The juice company Odwalla switched from non-pasteurized to flash-pasteurized juices in 1996 after tainted unpasteurized apple juice containing E. coli O157:H7 sickened many children and killed one.[4]

Int J Food Sci Nutr. 1995 May;46(2):107-15. A model study on rate of degradation of L-ascorbic acid during processing using home-produced juice concentrates. Roig MG, Rivera ZS, Kennedy JF. Source Departmento de Química Física, Facultad de Farmacia, Universidad de Salamanca, Spain. Abstract The rate of degradation of L-ascorbic acid in solution has been investigated under varying conditions, such as temperature, level of dissolved oxygen, pH, amino acids, sugars and processing conditions. Changes in pH between pH 1.5 and 7.0 accelerate L-ascorbic acid degradation. The most important factor that determines its stability is storage temperature, on which the rate of degradation of L-ascorbic acid is directly dependent. Similarly, the deleterious effect of variables such as oxygen and pH are influenced by temperature. Therefore, low temperature storage is imperative in order to regard L-ascorbic acid delay. A definite role of amino acids in L-ascorbic acid degradation has not been identified.

Br J Nutr. 1950;4(2-3):95-100. The losses of ascorbic acid during the large-scale cooking of green vegetables by different methods. ALLEN MA, BURGESS SG. http://journals.cambridge.org/download.php?file=%2FBJN%2FBJN4_2-3%2FS0007114550000266a.pdf&code=25d957615a175aa9ead73b8e039e5e6c

The processing of orange juice - looks pretty disturbing: http://www.enotes.com/orange-juice-reference/orange-juice

Cien Saude Colet. 2010 Jan;15(1):51-62. [Vitamin C loss in vegetables during storage, preparation and distribution in restaurants]. [Article in Portuguese] You can use Google Translate! http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-81232010000100010&lng=en&nrm=iso&tlng=en Moraes FA, Cota AM, Campos FM, Pinheiro-Sant'Ana HM. Source Departamento de Nutrição e Saúde, Universidade Federal de Viçosa, Viçosa, MG. flaviapmoraes@yahoo.com.br Abstract The main objective of this study was to evaluate vitamin c loss following vegetable manipulation stages, reception, storage, preparation, and distribution, in commercial and institutional restaurants. Seven vegetables were used: lettuce, carrots, chicory, collard greens, cauliflower, cabbage and tomatoes. Vitamin c analysis was made by high-performance liquid chromatography (hplc). After all manipulation stages, cumulative vitamin c loss was high in vegetables prepared in institutional restaurants and commercial restaurants corresponding to 44.38%-67.03% and 32.90%-71.32%, respectively. In both restaurants, storage accounted for the most expressive loss of vitamin c in the majority of the vegetables. The adoption of measurements to control vitamin c loss in vegetables is suggested, such as purchase and reception according to demand, storage at refrigerated temperatures, monitoring of hygiene and sanitation times, slicing near serving time, cooking preferably steamed, by pressure or stewed, monitoring of cooking time and temperature, and control of the exposure time between preparation and distribution. The results obtained for vitamin c content contribute to the nutritional characterization of vegetables, since studies related to this area are scarce in brazil and in the world.

So just have a glance at the ingredients list and I think you'll have an answer. One of the first (and thusly most plentiful) is 'Apple Juice.' First and foremost, the reason fruit juices, unless freshly squeezed or juiced, are not Paleo is that they can be concentrated and include added sugars (without actually being transparent about this on the label).

This is no different. Best case scenario, there is no added sugar and you're getting a 56 g shot of fructose as apples are high in fructose relative to glucose. Worst case scenario, a significant portion of that comes from either refined sugar or more likely high fructose corn syrup -- yuck.

Despite the outcry against fructose, if I'm looking for a treat every once and awhile, I'll juice my own "Naked smoothie" in my juicer. You'd be surprised at how awesome the fresh stuff tastes without added refined sugars and at what quantities you're consuming "evil" fructose.

As a postscript, Natasha Campbell-McBride champions fresh juices via the GAPS diet which is also based on WAPF principles. If you need guidance on how to include fruits in your diet while keeping levels of fructose low, pick up a copy of Gut and Psychology Syndrome.

Naked Juice has natural flavors in it. Which is either soy or wheat or robot juice.

It'his lot of fructose so might be a lot of empty calories. Avoid if you are trying to lose weight or have blood sugar issues.

the problem with "paleo" is that it is an impossible task. paleo says eat fresh fruit, veggies, nuts, seeds, and meat. Except not too much fruit because it has too much sugar, and not too many nuts because they can be bad also, or too much meat (especially beef or pork) because that is bad also. and don't eat beans or peas (which are fruits/seeds, but still bad). also, don't eat potatoes (which are botanically a vegetable, but starchy and bad). so basically live off of broccoli, spinach and coconut (because i'm sure "paleo-man" had no problem keeping dozens of coconuts on hand for every possible recipe he may use?!)

naked juice is paleo because it's just fruit and veggies. some people will always try to come off as more of an expert and tell you it's not QUITE good enough, but it is. you could eat 1000 apples and it might not be healthy, but it would be "paleo".

i'm gonna go have a green machine right now. bottoms up.

Barleygrass and wheatgrass are not the same as barley and wheat. The latter two are not paleo, the former are paleo. They are straight up grasses. What could be more paleo than grass?