How many syns should I have a day?

Five syns is the lower edge of the typical Slimming World range and it suits people pushing for faster loss who already have a small frame, sedentary routine, or a slower metabolism after several weeks of plateaued losses. It is not a starvation tactic — your Free Foods, Speed foods, HExA and HExB still cover the bulk of the day's calories and protein. Most members find that dropping below 5 makes the plan feel restrictive and triggers binge cycles, so use it as a short-term tool rather than a default. If you feel hungry, low energy, or obsessive about food at 5 syns, climb back to 10–15 and let consistency do the work.

Yes — 15 is a guide, not a hard cap. Slimming World itself sets the official allowance at 5–15 syns/day, but very active men, taller members, and people in maintenance often run at 18–20 without losses stalling. The honest test is your weekly weigh-in: if losses are healthy at 18 syns, that is your real allowance. If the scales stall for two weeks running, drop back to 12–15 and rebuild from there. Going over occasionally for a meal out or a celebration will not undo a week of good Free Food choices.

It can, and recalculating every stone or so is sensible. As you lose weight your basal metabolic rate drops slightly, so the allowance that drove a 2 lb/week loss at 16 stone may only deliver 0.5 lb/week at 12 stone. The fix is not always fewer syns — sometimes it is more activity, tighter Free Food portions, or moving from 'faster loss' to 'steady loss' mode so the deficit is sustainable. Re-run this calculator after every stone lost, or whenever your activity level genuinely changes (new job, baby, injury, gym membership).

No — Healthy Extras sit outside your syn allowance. HExA covers your daily calcium source (typically 350 ml semi-skimmed milk, or 30 g hard cheese). HExB covers your daily fibre source (typically 2 slices of wholemeal bread, 40 g porridge oats, or a high-fibre cereal). Most members take 1 of each per day. Very active men can take 2 of each without it slowing losses. Anything over your HEx limit moves into syns at the listed value — for example, a third slice of wholemeal bread costs roughly 5 syns.

Slimming World gives every member the same 5–15 syn range and asks consultants to nudge people up or down based on results. This calculator does that nudge for you using sex, weight, activity, and goal — three of the four variables an in-group consultant uses. It is a starting estimate, not medical advice. Pair it with honest weigh-ins for two to three weeks, then adjust by 1–2 syns either way based on what the scales show. If you have a medical condition, are pregnant, or are breastfeeding, follow your healthcare professional's guidance over any calculator.