Very many things: In most cases the spelling on the package saying vegetable-oil would mean it is made from palm-oil, which is oil extracted from the seeds of the African oil-palm (Elaeis guineensis). But it may be be all kinds of oil made from plants. Sunflower-seed-oil, olive-oil, rapeseed-oil (canola), avocado-seed-oil are examples of more healthy and more environmental-friendly oils. You have all reasons to believe it is palm-oil if:
1.) It says vegetable-oil only.
2.) The amount of saturated (hard and unhealthy) fat is something like approximately half of the total fat-content (if the product otherwise does not contain significant amounts of butter and other animal-fat, or coconut-fat).
We are told that vegetable oils are good for our health, they make the cholesterol levels in our blood lower and may give us a longer life, hopefully without hart diseases or stroke, even with less chances of suffering from e.g. Alzheimer's disease.
This is true sometimes, but unfortunately far too often false - it be can both, or something between - depending on which plant they were extracted from. And also how they have been processed, how old they are, etc.
Because vegetable-oil can be so many things, and all they are all so very different, on so many levels - the amount of types of fatty acids they contain, the impact they have on our health (e.g. cholesterol levels and inflammatory response), the impact on our environment, and important for the food industry: the shelf-life of their products, and how easy they are to process, and clean away after.
1.) The simple answer is a mix in your diet of rapeseed (canola) -oil (when you fry at higher temperatures), cold-pressed olive-oil (when frying at lower temperatures), some flaxen (line seed-oil), some sunflower seed-oil (good for frying). And if you don't eat much fish, some fish liver oil or similar containing omega-3-fatty-acids. And if you use butter, select the organic alternative, which most likely contain more omega-3, since the cow in this case got more grass and less soya to eat (they cow also becomes what it eat;-).
2.) The complicated answer (is something you have to wait for, but here is a rudimentary excel-sheet to study)
Why is palm-oil listed as vegetable-oil in the list of
ingredients in your package of biscuits?
Why does the industry favour palm-oil?
Why is palm-oil bad for the forest and the climate?
Palm-oil has the potential for sustainable smallholder production and could provide stable income for individual farmers. However this is not what happens at present: The establishment of palm-oil plantations is now the biggest cause of deforestation in Indonesia and Malaysia and it is likely to cause the extinction of tens of thousands of species among them possibly the Orang-utan, the Sumatran Tiger (only 400 left in the wild), and the Javan and Sumatran Rhinoceros from wild.
RSPO - Roundtable on Sustainable Palm Oil: What does sustainable actually mean ?(This sad story of Green-washing is coming)
The postive: A Successful Campaign: The Rainforest Campaign in Norway (Regnskogsfondet) have togeteher with Green Living (Grønn hverdag) made Norwegian food-industry reduce the use of palm-oil by 65 percent in just two years. Norway: Palm oil consumption reduced by two thirds
What others are saying:
Friends of the Earth - Experts warn Tripa orangutan extinction imminent
Palm Watch Africa
Say no to Palm Oil
Say no to Palm oil! group on Facebook
Nama saya Trond Kvitvik. I am a 51 year old
botanist, born and educated in Norway, now living in Finland. I
sadly believe our generations most of all will be remembered for
making so many wonderful species extinct, not for being worried
about greenhouse gases, visiting the moon, inventing the computers
or making cars. How is it possible we spend so much time and money
to search for treasures in the "ever-lasting-extending" space,
while the real fortunes are burning away in Indonesia or are being
cut away in the Congo Basin? Our grandchildren's grandchildren
will say: How could they be so ignorant? How could they let it
happen when it would have been so easy to do something about it?
It is our heritage we let go to waste, it is really hard to accept
we can be so stupid.
If you want to contact me by email add the "@" between my two names, and add ".com" to the end. I would be really glad for any help or comments!