Think sweet ~ stay slim

Think sweet ~ stay slim

Notwithstanding the overwhelming evidence that an excess of calorie intake per se, irrespective of the source of calories, causes obesity, there remains a populist and a policy view that sugar, rather than fat is the primary culprit. Although the biological argument that not all calories are equal and that carbohydrate calories are more fattening has been debunked by sound experimental evidence[1], the case moves more to appetite as the causative factor. Since people don’t eat what they don’t like, an understanding of the “liking” of particular foods becomes important.

To study this phenomenon, two approaches are possible. One is to use a ‘cross sectional’ approach which seeks to compare obese persons and lean persons for their food preferences at a single moment in time. The problem here is that the obese persons may have acquired a view of what putatively ‘causes’ obesity and in so doing, they may bias their response to any study questionnaires. Thus obese subjects at a given point in time might express a lower liking for sugar-sweetened beverages compared to diet beverages because that is what they are conditioned by society to believe. Moreover, obese subjects may in fact use sugar free beverages to manage their weight. The alternative to this approach is to complete a ‘prospective’ study in which people’s likings for food are measured at a single point in time and the group subsequently followed over several years to see who gets obese and who stays slim. That way, the presence of obesity is independent of the answers to the original questionnaire.

A recent paper from the French research consortium “NutriSanté” has examined the effect of liking for fat, sugar and salt on subsequent development of obesity[2]. The NutriSanté study is an internet-based study, initiated in 2009, with a current enrolment of some 65,683 volunteers. Data is gathered at the point of recruitment on many aspects of health such as diet, physical activity, weight, smoking and alcohol habits, weight management and so on and is repeated annually.  Each month, volunteers are invited to complete questionnaires related among other things to food behaviour.  The questionnaire covered salt (11 questions) and sweet (21 questions) tastes plus preferences of fat-and-salt (31 questions) and fat and sweet sensations (20 items).  Some 49,066 subjects agreed to answer these questions. However, when the data were cleaned up to ensure that all respondents had completed every aspect of the overall NutriSanté study, there were full data on 24,776 subjects.

In the 4 years of follow up, 24,112 subjects remained non-obese while 664 subjects became obese. The key sensory findings are thus:

Sensory liking scores	Non-obese subjects	Obese subjects	Statistical conclusions
Liking for fat	3.79	4.03	Highly different
Liking for sweet	3.73	3.66	No difference
Liking for salt	3.77	3.93	Highly different

Those who gained weight had a higher preference for fat and salt but not for sugar.  Another approach to the data analysis is to look across the “liking” score data and to divide subjects according to their ranking, starting at the “low liking” (lowest quarter or ‘quartile’) right up to the “highest liking”  (highest quartile). These data are controlled statistically for all known confounding variables.

	Statistical difference in risk of developing obesity between lowest and highest quartiles of “liking”
	Men	Women
Fat liking	Yes, up 85%	Yes, up 49%
Fat + salt liking	Yes, up 106%	No
Fat + sweet liking	No	Yes, up 37%
Sweet liking	Yes, down 59%	No
Natural sweetness liking	No	Yes, down 69%

The authors also looked at baseline food intake (as opposed to liking) and observed no association between sugary food intake and obesity. Indeed, the evidence was that those who did not develop obesity had higher sugar intakes at baseline. The results are summarised below.

Food group intake g/d	Non-obese subjects	Obese subjects	Statistical conclusions
Fruits	279	234	Highly different
Meat	45	57	Highly different
Processed meat	3.77	3.93	Highly different
Milk and yogurts	169	192	Highly different
Cheese	38	36	Not different
Oil	9.3	8.1	Highly different
Whole grain products	36	28	Highly different
Sugar and products	24	19	Highly different
Fatty sweet products	69	65	Not different
Sugar-sweetened soft drinks	39	41	Not different

The authors conclude thus: “This prospective study reinforced results from cross sectional studies, by highlighting that fat liking was prospectively associated with an increased risk of obesity and diet appeared to substantially explain this relationship. Results have also shown that sweet liking is associated with a decreased risk of obesity, and there is no significant association between salt liking and obesity risk”.

Once again, we have a fully public funded comprehensive and prospective study from a highly reputable group, with the study suitably powered for optimal statistical analysis, which challenges conventional wisdom. It will be ignored but, you see, it won’t go away and one day, when the false gods of the demonic sugar sect are reduced to clay, these papers will come back to haunt the high priests of public health nutrition. I wanna be there!!!

By the way, the blog stands now at 231,325 views. Thank you all and a happy New Year to all of you.

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[1] See blogs of November 21^st 2016 and of August 14^th, 2015.

[2] Lampuré et al. International Journal of Behavioral Nutrition and Physical Activity (2016) 13:74