So what's with this Sugar then ? FAQ

Firstly, if you don't want to track sugar daily you can turn it off in the settings of your food diary at http://www.myfitnesspal.com/account/diary_settings (top left)

Secondly, if you want to use a higher target than MFP's standard you can change that in Custom Goals at http://www.myfitnesspal.com/account/change_goals_custom (lower left)

1. What is MFP's sugar target ?

The value appears to be set at 8% of your daily calories. So if your calorie goal is 2000 cals the sugar part is 160 cals or 40 grams per day.

2. Where does the target come from ?

It is almost certainly a limit for "added sugars" or "non-milk extrinsic sugars" based on Nutritional Guidelines.

The American Heart Association say "For most American women, that’s no more than 100 calories per day, or about 6 teaspoons of sugar. For men, it’s 150 calories per day, or about 9 teaspoons." That's 25 or 38 grams per day respectively of added sugars based on "no more than half your discretionary calories". http://circ.ahajournals.org/content/120/11/1011.full.pdf

The World Health Organisation sets a guideline for added sugars to be less than 10% of energy intake. http://www.who.int/bulletin/volumes/81/8/en/Steyn0803.pdf

The EU have discussed a limit of 90g (18% of energy on a 200 cal diet) for total sugars and observed that 45g is a typical adult intake of intrinsic or naturally occurring sugars from fruit, veg and dairy. http://www.efsa.europa.eu/en/efsajournal/doc/1008.pdf

Australia has a Dietary Recommended Intake value for total sugars of 90g per day, as has the EU (for a 2000 calorie diet - so 18% of energy). Annex 13 of Regulation (EU) No 1169/2011

3. What are "added sugars" ?

This depends on your regulatory authorities. In the UK "added sugars is defined as any mono- or
disaccharide or any other food used for its sweetening properties. This would include, but is not exclusively limited to: sucrose, fructose, glucose, glucose syrups, fructose-glucose syrups, corn syrups, invert sugar, honey, maple syrup, malt extract, dextrose, fruit juices, deionised fruit juices, lactose, maltose, high maltose syrups, Agave syrup, dextrin and maltodextrin. The sugars contained in dried fruit are assumed to be intrinsic and are not included as added sugars. The sugars in milk powder are not included as added sugars, in line with COMA dietary guidelines which deemed sugars in milk as a special case and did not set guidelines to limit their intake."

Others are similar, the target being sugars deliberately added to a food product rather than those which happen to occur naturally in the other ingredients of the product. These regulatory definitions are often a political compromise between science, health and food industry interests - the exclusion for sugar in milk for example is probably a result of pressure from the dairy industry and may have little scientific credibility.

4. Which sugars are natural ?

All of them. Sucrose is found in sugar cane and sugar beet as well as in many fruits - half the sugars in orange are sucrose. Glucose is common in fruit but is less sweet than fructose. Fructose is mainly found in honey and fruit and has the highest sweetness intensity of the sugars. Lactose is a sugar and the main carbohydrate in milk products. High fructose corn syrup (HFCS) is perhaps the most manipulated sugar product in common use - starch from corn is broken down to glucose and 42-55% of that are then "isomerized" by enzymes or similar processes into fructose molecules to create a liquid syrup with the sweetening characteristics of sucrose but at lower cost.

5. How do natural and added sugars differ chemically ?

They don't. The sucrose molecule is the same wherever you find it. It can be split into a glucose and a fructose molecule under acid conditions or by an enzyme. The resulting fructose and glucose molecules are the same as the native fructose and glucose molecules from fruit. Molecular diagrams at https://cdavies.files.wordpress.com/2009/01/glucose-fructose-sucrose.jpg

Note that fruit juice is a natural sugar but becomes an "added sugar" if used to sweeten a food product.

6. Are natural sugars processed differently in the body ?

No. A glucose molecule or a fructose molecule looks the same to your liver, muscles etc wherever it came from. Fructose molecules follow a different pathway via the liver in contrast to other sugars or carbohydrates, some scientists believe this makes fructose potentially problematic and a "cause" of obesity, diabetes, etc. Robert Lustig, John Yudkins, David Gilespie and others have written books with emotive titles about the "dangers" of sugar or fructose.

In eating a whole fruit the fiber content and dilute nature of the sugars reduces the rate and amount we consume. The same cannot be said of fruit juice (fibre removed) which can contain 50% more sugars than regular cola drinks. Fruit has some vitamins and minerals and is generally perceived as "healthy", especially by its marketers, but ultimately the sugar in a fruit is the same stuff as the sugar in sugar cane and looks identical inside your organs.

7. What should I do ?

This is a matter of personal choice. The approach of 90g total sugars per 2000 calories (18% of energy) seems to be accepted in a number of countries, with MFP's minimum 1200 calorie setting this would be 54g of sugars. At this level the fructose intake will be below the level that some regard as potentially problematic.

If your consumption of fruit (or any food) takes you above this level then you may wish to research further the types of sugar you are eating and the potential health implications. You may choose to set a higher level, or simply to ignore it and just track carbohydrates.

If you read or follow Robert Lustig, John Yudkins or David Gilespie and buy into their arguments then you may want to stick with the MFP value or set a different one based on what you have learned.