Eat for more energy: The thyroid gland is closely linked to overall metabolic rate and if it is not working properly, fatigue is likely, says top nutritionist Ian Marber. A number of foods are classed as goitrogens, ie contain substances that suppress thyroid function, and thus can add to fatigue, including broccoli, Brussels sprouts, peaches, soya and peanuts (www.thefooddoctor.com for more nutritional information).