How do you define a "true light source"? Colours are not "disguised".
I think you are confusing terms /concepts. It's colour temperature, brightness (Lumens) and directionality that are of concern of restaurateurs. This chart will help explain:
http://www.lightbulbs-direct.com/article/colour-temperature/ , but this is the important one:
http://cool.conservation-us.org/waac/wn/wn21/wn21-3/wn21-308.html. See the comments about A.A. Kruithof's research.
Natural daylight at high noon is typically defined as 5600K. Bulbs rated in the 5000 - 6000 range are typically called "daylight". More importantly, it's the combination of colour and brightness that we humans perceive in different ways.
Many less expensive LED bulbs are rated 2700K / warm white including One.of.a.kind's bulb:
http://www.homedepot.com/p/Philips-...t-Bulb-4-Pack-433227/204780591#specifications Because the light is more yellow/orange/white (natural light is more blue/white) and most LEDs are bright and directional many people find 2700K LEDs harsh and make the colour of your skin and food look grey. If you took the same bulb and either reduced the output or diffused the light, most people would find it less objectionable while eating.
BTW, 5000K lower wattage LED bulbs are most recommended for restaurants when used for direct table lighting. If you are working in the industry, please look at your supplier's information. Different LED bulbs ratings and colour temperatures are used for different purposes in professional lighting.