The researchers behind the review said that the findings, which suggest a 'seesaw' effect in sugar and fat intake, may offer a reason to why people find it hard to follow guidelines that suggest to cut fat and sugars intake at the same time.
Writing in Critical Reviews in Food Science and Nutrition, the research team looked at evidence from 53 scientific papers, finding a 'strong and consistent' inverse association in the percentage of energy coming from fats and sugars - people with diets low in sugars were likely to be high in fat, and vice-versa, the authors said.
“A key reason that we see this sugar-fat seesaw is likely to be because sources of sugars such as fruit, breakfast cereals and juices are low in fat, while sources of fat such as oils and meat products are low in sugar," suggested Dr Michele Sadler, who led the research team.
“This study highlights the need to focus dietary messages on eating a healthy balanced diet and not categorising individual nutrients as good or bad, which could result in unbalanced dietary habits," she added.
Sadler and her colleagues noted that the review was supported by a grant from the Sugar Nutrition UK - formerly the Sugar Bureau (UK) - "under the condition that Sugar Bureau personnel or associates had no part in the selection or assessment of relevant data, in the interpretation of the results or writing of the paper."
The new review analysed the findings of 53 peer reviewed research papers investigating patterns in the intake of sugar and fat - finding that there is a strong and consistent inverse association between total sugars and total fat intakes expressed as percentage energy.
"Evidence for an inverse relationship between percentage energy from fat and extrinsic sugars was weaker and less consistent than for fat and total sugars," said Sadler and her team - who noted that reciprocal relationships were also observed for sugar-saturated fat, sugar-protein, sugar-alcohol and sugar-starch expressed as percentages of energy.
"This review confirms the existence of the sugar-fat seesaw on a percentage energy basis and concludes that it is most likely explained by a combination of mathematical and food compositional effects," said the team.
"This finding is relevant because dietary guidelines are expressed as percentage energy, and implies that at the population level multiple guidelines may be difficult to achieve in practice."