I do believe for some people diet is important. It's just so hard to determine what in your diet is affecting your tinnitus. It's unlikely that everything affects it. I'd keep a diary and take away one food at a time for a week or more. Then reintroduce one at a time. That's what I did/am doing. My tinnitus fluctuates--but in part this is just my brain and has nothing to do with my diet.
If sugar is a trigger for one's tinnitus, I do have an interesting 2004 study on hyperglycemia and tinnitus. Hyperglycemia results from insulin resistance. It's very common in women.
Here's the abstract and conclusion:
Tinnitus affects millions of people worldwide, and it signals the presence of several underlying diseases, including hyperinsulinemia. The aim of this study was to evaluate the response to dietary treatment in 80 patients with associated tinnitus and hyperinsulinemia. On the basis of data obtained by a questionnaire, two groups were established: One included patients who followed the prescribed diet; the other group included patients who did not comply with the treatment. The likelihood of improving tinnitus symptoms was fivefold higher in hyperinsulinemic patients who followed the diet than in those who did not (relative risk [RR], 5.34; 95% confidence interval [CI], 1.85-15.37;
p < .05). In addition, resolution of tinnitus was reported by 15% of the patients who followed the diet as compared to 0% of those who did not. These findings underscore the importance of including hyperinsulinemia in the routine diagnostic investigation of patients with tinnitus regardless of whether associated with neurosensory dysacusis or vertigo (or both).
...
The results of our study show the great potential of dietary management to improve tinnitus in patients with carbohydrate metabolism disorder, independently of tinnitus intensity. Dietary management alone was associated with a fivefold increase in the probability of significant reduction in tinnitus. The fact that 76% of the patients who followed a specific diet achieved at least partial decrease of tinnitus symptoms reinforces the need for considering this metabolic disorder as a possible etiological diagnosis in the presence of tinnitus. As far as we know, the significant lessening of tinnitus symptoms observed in this study (with resolution in 15% of cases) has not been observed with any other types of treatment (drug therapy, for example).
The difficulty of treating tinnitus patients (who frequently present with associated depressive or anxiety disorders) is well-known. Therefore, a thorough investigation of associated metabolic alterations using the 5-hour glycemic and insulinemic curves, as performed in this study, should be part of the routine evaluation of patients with tinnitus and may result in significant easing in symptoms and quality of life. Only with the optimization of the diagnosis of metabolic alterations will we be able to correct or at least attenuate those disorders, which may have an extremely relevant impact on tinnitus.
Source:
http://www.tinnitusjournal.com/detalhe_artigo.asp?id=458
You might have your primary care doctor test you for insulin resistance. If you're fine, you can go back to eating sugar!

I know how frustrating and inscrutable this disease can be!