Labour MP Keith Vaz said Coca-Cola was marketing a "real health hazard".
But Conservative city councillor Ross Grant told the Leicester Mercury that opening the sweet shop in 2013 "put him into the hypocrite category".
Keith Vaz has not responded, but previously said he opposed the way Coke is promoted, rather than the product.
"What we want to do is to make sure Coca-Cola indulges in a proper debate and has a proper engagement with health campaigners, such as Members of Parliament who are part of the All Party Diabetes Group, to make sure that they are much more responsible in the way in which they promote and sell their products," said the Leicester MP.
Public Health England also has concerns about the marketing of Coca-Cola.
Its chief nutritionist, Dr Alison Tedstone, said: "The evidence shows that this type of advertising increases children's preference for and consumption of sugary drinks, which are linked to tooth decay and too many calories leading to obesity.
"Worryingly, children and teenagers are having three times more sugar than the maximum recommended amount and the biggest source is sugary drinks."
Public Health England said evidence showed that restrictions on marketing, advertising and promotion of high-sugar products are likely to be more effective than adding a tax to sugary drinks, along with reducing the added sugar in processed foods and drinks.
Dr Tedstone said: "There is no place for sugary drinks in a child's daily diet - lower fat milks and water are ideal but swapping to no added sugar, diet and sugar free alternatives is fine."
35g
sugar in a 330ml can of Coca-Cola
53g
sugar in a 500ml bottle of Coca-Cola
19g advised maximum sugar intake per day for children aged 4 to 6
24g maximum daily sugar intake for children aged 7 to 10
30g maximum sugar intake for adults and children over 11
Coca-Cola Great Britain said its Christmas truck would offer two sugar-free variants.
"We're delighted to be visiting Leicester this year as part of the Coca-Cola Christmas truck tour," it said in a statement.
"Our Christmas truck tour also operates in line with our responsible marketing policy so we don't sample our drinks directly to under-12s."
Mr Vaz was diagnosed with type 2 diabetes 13 years ago at a health awareness event in his constituency.

The 31-year-old has joined the Spitfires on a deal until the end of the season.
Tubbs could be handed his Eastleigh debut in the National League game at Kidderminster on Tuesday.
Ex-Bournemouth striker Tubbs has scored five goals for League Two side Portsmouth this season but he has not featured for Pompey since October.

People with a DNA variation in a gene called PDSS2 tend to drink fewer cups of coffee, a study carried out at the University of Edinburgh has found.
It suggests the gene reduces cell ability to break down caffeine.
This causes it to stay in the body for longer and means those with the gene get the same caffeine hit through less coffee.
One scientist working on the project said it suggests the "drive to drink coffee may be embedded in our genes".
The researchers studied the DNA of 370 people living in a small village in southern Italy and 843 people from six villages in north-east Italy.
The subjects were asked to complete a survey including a question about how many cups of coffee they drank each day.
The team found people with the PDSS2 DNA variation tended to consume fewer cups of coffee than people without the variation - equivalent to one fewer cup daily on average.
Researchers replicated the study in a group of 1,731 people from the Netherlands. The result was similar but the effect of the gene on the number of cups of coffee consumed was slightly lower.
The scientists said the change could be down to the different styles of coffee drunk in the two countries.
In Italy, people tend to drink smaller cups such as espresso whereas in the Netherlands the preference is towards larger cups which contain more caffeine overall.
Dr Nicola Pirastu, a Chancellor's Fellow at the University of Edinburgh, said: "The results of our study add to existing research suggesting that our drive to drink coffee may be embedded in our genes.
"We need to do larger studies to confirm the discovery and also to clarify the biological link between PDSS2 and coffee consumption."
The study is published in the journal Scientific Reports and was conducted at the universities of Edinburgh and Trieste, the Burlo Garofolo Pediatric Institute in Italy, the Erasmus Medical Centre and PolyOmica, a data analysis company based in Groningen, the Netherlands.
A diabetic MP who asked Coca-Cola not to take its Christmas truck to Leicester has been accused of hypocrisy for opening a sweet shop in the city.
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Eastleigh have confirmed the loan signing of Portsmouth striker Matt Tubbs.
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Researchers have identified a gene that appears to curb coffee consumption.