Recent research revealed that guidelines warning people to avoid eating fatty foods such as butter and cheese "should not have been introduced".
Now dietary experts have added that many perceived ideas on what is healthy or unhealthy do more harm than good as healthy eating is down to the individual.
Coffee, sugar, salt, wine and chocolate are just some of the food and drink products that are said to be bad for you one minute and then good for you the next.
But dietitian Catherine Collins said the important message to send out is that most things are good for you in moderation and balance is the key.
"Dietary advice is constantly evolving and we're constantly tweaking it," she said.
"Our current health message is geared to our body size and current risk of disease. The important thing is to always interpret the advice for the individual."
She used the example of coffee, which has been linked to high blood pressure.
But she said that most people who are used to drinking coffee develop a tolerance to caffeine and only those who already experience high blood pressure should think about avoiding it.
Foods which have provoked a turnaround in advice in the past include eggs, which those with high cholesterol were told to avoid.
However research has failed to link dietary cholesterol to human cholesterol levels and so this no longer appears relevant.
Meanwhile health experts once extolled the virtue of a diet full of fruit, vegetables, whole grains and legumes as it was thought to lead to a reduced risk of colon cancer.
However it was later found out that a high-fibre diet might not prevent colon cancer at all.
Collins, the principal dietitian at St George's Hospital in south London, said that although it has emerged that warnings about fat consumption were not backed up by scientific evidence at the time, it remains clear that large amounts are unhealthy.
"None of the current recommendations say that it's the devil's food. Some modest dairy, some modest portions of oil are fine," she added.
Dr Tim Chico, consultant cardiologist at the University of Sheffield, said the research used a technique to combine the results of multiple studies called meta-analysis that was not applied to medical studies when the guidelines were first drawn up.
"In the absence of a clear answer, it seems reasonable that doctors and scientists try to produce the best advice they can with the totality of evidence available," he said.
"Almost always, this advice will change, sometimes completely, with the addition of new knowledge.
"Sometimes the most important health questions are the hardest to address scientifically, often for rather mundane or practical reasons like cost or the difficulty in getting people to alter their diet.
"For these reasons, I do not expect that we will ever be able to say for certain what the best diet is for long-term health."